• 한국정밀공학회지
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• 제18권5호
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• pp.65-73
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• 2001

In this paper, a mobile system using multi-wheel steering and driving mechanism is proposed to maximize maneuverability of the wheeled mobile system. Among various possible configurations, the two-wheel steering and driving systems, which is minimal in structural requirement, is proposed to reduce the complexity in actual design and difficulties in control. The system possesses three or four degrees of freedom depending on the orientations of two wheels, one or two for driving and two for steering, which implies that the system's mobility is always less than three DOF. The proposed system, nonetheless, can exactly emulate characteristics of the omnidirectional motion as long as the planned path is smooth i.e., the curvature changes continuously while velocity is not zero. Efficient kinematic and dynamic control algorithms are proposed for position and orientation control of the proposed wheeled mobile system.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.919-924
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• 2016

This paper proposes a robust control design method for improving the cornering stability of a personal electric vehicle equipped with in-wheel motors. In general, vehicles undergo severe parameter variations and unpredictable disturbances with respect to a wide range of driving conditions (e.g., road surface conditions and vehicle velocity conditions). For this reason, robust control design techniques are required to guarantee consistent driving performances and robustness against various driving conditions. In this paper, an adaptive sliding mode control method is employed to enhance cornering stability by controlling the direct-drive in-wheel motors independently. Additionally, in order to confirm the effectiveness of a proposed control method, real driving tests with an experimental personal electric vehicle are performed.

• 한국군사과학기술학회지
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• 제5권1호
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• pp.45-58
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• 2002

In this paper, we designed the circuit of drive control for towing winch. It is composed of reference voltage circuit for driving voltage reference, low pass filter circuit for noise reduction, dead zone circuit for initial transient input, and driving circuit for drum direction/velocity control. Also it is realized a drive control circuit for towing winch drum in accordance with PWM(pulse width modulation) method to suit it's purpose of a large capacity driving system. The performance of the designed circuit is analyzed by experiments and the appliablity for driving the towing winch drum satisfactorily is evaluated through a various testing.

• 자동차안전학회지
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• 제13권4호
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• pp.123-128
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• 2021

This paper present box feature estimation from LiDAR point cluster using maximum likelihood Method. Previous LiDAR tracking method for autonomous driving shows high accuracy about velocity and heading of point cluster. However, Assuming the average position of a point cluster as the vehicle position has a lower accuracy than ground truth. Therefore, the box feature estimation algorithm to improve position accuracy of autonomous driving perception consists of two procedures. Firstly, proposed algorithm calculates vehicle candidate position based on relative position of point cluster. Secondly, to reflect the features of the point cluster in estimation, the likelihood of the particle scattered around the candidate position is used. The proposed estimation method has been implemented in robot operating system (ROS) environment, and investigated via simulation and actual vehicle test. The test result show that proposed cluster position estimation enhances perception and path planning performance in autonomous driving.

• 한국정밀공학회지
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• 제10권4호
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• pp.190-199
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• 1993

In this study a three-axes mobile robot which has two independently controlled driving wheels and a function of simultaneously steering the driving wheels has been developed. Two-motion modes of the mobile robot, the first is a differential velocity motion of two driving wheels and the second is a equal driving and steering motion, have been analyzed and the kinematic and dymanic analyses about the each motion mode have been carried out. As a result of dynamic analysis, the torque used on a motor control and acceleration have been derived explicitly. Hence, a computation time is saved effectively and a real time control of the mobile robot considering the dynamics has become possible. Through a simulation the results considering the dynamics have been compared with that no regarding the dynamics and the possibility of real-time control has been proved.

• 한국소음진동공학회논문집
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• 제16권7호
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• pp.697-703
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• 2006

This article proposes a new technique for the reduction of vibration and noise in the geared system by adjusting the distance between gear shafts. The vibration and noise may be produced by the abnormal force applied to the tooth face. And the force may be the cause of ununiform velocity in the driven shaft. If the velocity is obtained to be uniform by adjusting the distance between shafts. the vibration and noise may be reduced to some extent. In order to review, a dynamic analysis model for the gear train used in a mill turret and a test rig are developed. The velocities in the driven shaft are calculated by dynamic simulations for the model and noises in the test rig are measured with varying of the distance between shafts. The comparison of simulation and test data shows that the distance between shafts at the most uniform velocity has the lowest level of noise.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.133-138
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• 1993

This paper presents neural network based position estimation method in slippery environment as an approach to solve one of problems which are engaged in dead reckoning method. Position estimator is composed of slip detector and linear velocity estimator. Both of them are based on the fact that dynamic characteristic of mobile robot in slippery environment is different from the case without slip. To find out the dynamic relation among driving torque, angular acceleration of driving wheel and linear acceleration of mobile robot, accelerometer is used for measuring acceleration of mobile robot and neural network is used for dynamic system identifier in slippery environment.

• 한국산학기술학회논문지
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• 제12권1호
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• pp.19-25
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• 2011

최근의 차량 연비는 환경 규제 및 고가의 연료 가격으로 인하여 중요한 문제로 대두되었다. 연비 향상을 위한 기술 개발은 엔진, 파워트레인 등 차량의 많은 구성품들의 성능을 개선하였다. 따라서 연비는 많이 향상 되었으나 연비 측정은 현재도 주어진 모드(LA-4, FTP-75 등)에서 컴퓨터 모의시험 및 다이나모에서 수행한다. 본 논문에서는 실제 도로의 연비 향상 방안을 도출하기 위하여 약 213Km 영동고속도로를 제안하는 3가지 다른 알고리즘으로 모의 주행하였다. 이를 위해 GPS 수신 데이터 중에서 거리와 고도 데이터를 추출하여 각 구간의 경사도, 주행저항을 계산, 알고리즘에 따른 속도 프로파일을 약 213Km 전 구간에 대해서 완성하였다. 이 속도 프로파일로 컴퓨터를 이용한 AVL Cruise 프로그램으로 모의 주행하여 연비를 산출하고 Eco-driving 방안을 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1542-1543
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• 2007

This paper presents the effect of driving waveform for piezoelectric bend mode inkjet printhead with optimized mechanical design. Experimental and theoretical studies on the applied driving waveform versus jetting characteristics were performed. The inkjet head has been designed to maximize the droplet velocity, minimize voltage response of the actuator and optimize the firing frequency to eject ink droplet. The head design was carried out by using mechanical simulation. The printhead has been fabricated with Si(100) and SOI wafers by MEMS process and silicon direct bonding method. To investigate how performance of the piezoelectric ceramic actuator influences on droplet diameter and droplet velocity, the method of stroboscopy was used. Using the water based ink of viscosity of 11.8 cps and surface tension of 0.025N/m, it is possible to eject stable droplets through 64 nozzles average velocity of 4.05 m/s with standard deviation of 0.06 m/s and average diameter of $29.2\;{\mu}m$ with standard variation of $0.5\;{\mu}m$.

• 한국지능시스템학회논문지
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• 제20권3호
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• pp.394-399
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• 2010

본 논문은 중량물 운송을 위한 AGV(autonomous guided vehicle)의 주행 제어 방법에 관한 연구이다. 일반적으로 실제 산업 현장에서 하루 20시간 이상 작업하는 경로 추적 방식의 fork-type AGV는 팔레트 하역 작업 시에 목표 지점에 대한 높은 정지 정밀도와, AGV의 정지 정밀도를 높이기 위해 저속으로 주행 하는 기술이 요구 된다. 따라서 본 논문에서는 엔코더의 데이터를 계측 받아 AGV의 주행 속도를 측정 및 분석하여 AGV의 최저 주행 속도 유지 및 AGV의 정지 정밀도를 높이는 주행 제어 방법을 연구 하였다. 본 논문에서 제안한 주행 제어 방법의 실험은 팔레트 앞 4m 지점부터 직선 주행후에 팔레트 하역 작업을 수행하도록 하였고, 총 10회 실험 후에 이들의 정밀도를 분석하였다. 그 결과, 팔레트 하역 시 목표 지점에 대한 정지 정밀도의 최대 오차가 18.64mm이내로 높은 정지 정밀도의 안정적인 주행 제어가 가능함을 확인 할 수 있었다.