• Title/Summary/Keyword: Yaw rate

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Development of the Gas Charging Simulator for Reaction Control System of KSLV-I (KSLV-I RCS 충전모사 시스템 개발)

  • Jeon, Sang-Woon;Jung, Seul;Kim, Ji-Hun
    • Aerospace Engineering and Technology
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    • v.8 no.2
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    • pp.122-126
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    • 2009
  • KSLV(Korea Space Launch Vehicle)-I is designed as a launch vehicle to enter a 100 kg-class satellite to the LEO(Low-Earth Orbit). Attitude angles of the upper-stage, including roll, pitch and yaw are controlled by cold gas thruster system using nitrogen gas. To verify the flow rate of the gas charging system and to prepare a nitrogen gas charging scenario, the development of a gas charging simulator for RCS(Reaction Control System) is required. This paper describes the orifice design, development, and test of the gas charging simulator for RCS of KSLV-I.

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Development of Human Driver Model based on Neuromuscular System for Evaluation of Electric Power Steering System (전동식 조향 장치의 성능 평가를 위한 신경 근육계 기반 운전자 모델 개발)

  • Lee, Sunghyun;Lee, Dongpil;Lee, Jaepoong;Chae, Heungseok;Lee, Myungsu;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.9 no.3
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    • pp.19-23
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    • 2017
  • This paper presents a lateral driver model with neuromuscular system to evaluate the performance of electric power steering (EPS). Output of most previously developed driver models is steering angle. However, in order to evaluate EPS system, driver model which results in steering torque output is needed. The proposed lateral driver model mainly consists of 2 parts: desired steering angle calculation and conversion of steering angle into steering torque. Desired steering angle calculation part results in steering angle to track desired yaw rate for path tracking. Conversion of steering angle into torque is consideration with neuromuscular system. The proposed driver model is investigated via actual driving data. Compared to other algorithms, the proposed algorithm shows similar pattern of steering angle with human driver. The proposed driver can be utilized to efficiently evaluate EPS system in simulation level.

Development of Vehicle Integrated Dynamics Control System with Brake System Control (제동 장치를 이용한 차량통합운동제어시스템 개발)

  • Song, Jeonghoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.7
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    • pp.591-597
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    • 2017
  • This study is to develop a vehicle Integrated Dynamics Control System(IDCB) that can stabilize the lateral dynamics and maintain steerability. To accomplish this task, an eight degree of freedom vehicle model and a nonlinear observer are designed. The IDCB independently controls the brake systems of four wheels with a fuzzy logic control and a sliding model control. The result shows that the nonlinear observer produced satisfactory results. IDCB tracked the reference yaw rate and reduced the body slip angle under all tested conditions. It indicates that the IDCB enhanced lateral stability and preserved steerability.

Tilt variation and wake turbulence in the otter board of a bottom trawl during fishing operations

  • KIM, Yong-Hae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.4
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    • pp.337-348
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    • 2017
  • The tension of warp from trawler and sea-floor contact can generate tilt and wake turbulence around otter boards. Preliminary measurements of otter board tilt and 3-D flow velocity during bottom trawl operations were taken using a vector instrument to investigate the effects of wake turbulence at the trailing edge of the otter board. Tilt data (i.e., yaw, pitch, and roll) at 1 Hz and flow data (velocities in the towing, lateral, and vertical directions) at 16 Hz were analyzed to determine their periods and amplitudes using global wavelet and peak event analyses. The mean period (${\pm}standard$ deviation) of the tilt from the peak event analysis ($5{\pm}2s$) was longer or double than that of flow velocity ($3{\pm}2s$). The two periods also had a significant linear relationship. The turbulence rate of flow was 30-50% at the trailing edge and was closely related to roll deviation. The frequency of phase difference ratios (i.e., peak time differences between tilts and flow periods) was significantly different from random occurrence in two trials, possibly due to side tidal effects. However, in the other trials, flow peaks were random, as shown by the even peak times between tilts and flows. Future studies should focus on reducing tilt variation, wake turbulence, and bottom contact to stabilize otter board motion.

A Simulation Program for the Braking Characteristics of 8$\times$4 Vehicles (8$\times$4 차량의 제동특성 시뮬레이션 프로그램 개발)

  • 서명원;박윤기;권성진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.119-128
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    • 2001
  • Recently safety systems for the commercial vehicle have been rapidly developed. However, we still have many problems in the vehicle stability and the braking performance. Especially, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and the road is wet or slippery. To design the air brake system for commercial vehicles, since the air brake system has many design variables, there must have been intensive researches on a method how to prevent dynamic instability and how to maximize the vehicle deceleration. In this study, mathematical models about an 8$\times$4 vehicle and an air brake system including an ABS controller have been constructed for computer simulation. Also, simple examples are applied to show the usefulness of the computer program. Designers can use this simulation program for understanding the braking characteristics of 8$\times$4 commercial vehicles such as trajectory, braking distance, longitudinal deceleration, lateral deceleration, and yaw rate on various road conditions.

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Improvement of Vehicle Handling Performance due to Toe and Camber Angle Change of Rear Wheel by Using Double Knuckle (이중너클을 이용한 후륜 토 및 캠버각 변화를 통한 조종안정성 개선)

  • Sohn, Jeonghyun;Park, Seongjun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.1
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    • pp.121-127
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    • 2013
  • In this study, suspension geometry is controlled to improve vehicle handling performance. The toe and camber of the rear suspension is controlled independently by using a double knuckle structure designed to enhance the vehicle cornering stability. Camber and toe changes in the rear wheel during high speed turning maneuver are important factors that influence the vehicle stability. Toe in the rear outer wheel plays a dominant role in cornering. A control algorithm for the camber and the toe angle input is developed to carry out the control simulation of the vehicle such as single lane change, the steady state cornering, the double lane change and the step steering simulation. Effects of the camber and toe angle control are analyzed from the computer simulations. A double lane change simulation revealed that the suspension mechanism with variable camber angle and variable toe angle decreases the peak body slip angle and peak yaw rate, 50% and 10%, respectively.

Vehicle Orientation Estimation by Using Magnetometer and Inertial Sensors (3축 자기장 센서 및 관성센서를 이용한 차량 방위각 추정 방법)

  • Hwang, Yoonjin;Choi, Seibum
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.4
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    • pp.408-415
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    • 2016
  • The vehicle attitude and sideslip is critical information to control the vehicle to prevent from unintended motion. Many of estimation strategy use bicycle model or IMU integration, but both of them have limits on application. The main purpose of this paper is development of vehicle orientation estimator which is robust to various vehicle state and road shape. The suggested estimator use 3-axis magnetometer, yaw rate sensor and lateral acceleration sensor to estimate three Euler angles of vehicle. The estimator is composed of two individual observers: First, comparing the known magnetic field and gravity with measured value, the TRIAD algorithm calculates optimal rotational matrix when vehicle is in static or quasi-static condition. Next, merging 3-axis magnetometer with inertial sensors, the extended Kalman filter is used to estimate vehicle orientation under dynamic condition. A validation through simulation tools, Carsim and Simulink, is performed and the results show the feasibility of the suggested estimation method.

A Simplified Horizontal Maneuvering Model of a RIB-Type Target Ship (RIB형 표적정의 수평면 조종운동 간략모델)

  • Yoon, Hyeon-Kyu;Yeo, Dong-Jin;Fang, Tae-Hyun;Yoon, Kun-Hang;Lee, Chang-Min
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.6
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    • pp.572-578
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    • 2007
  • A Rigid Inflatable Boat (RIB) is now widely used for commercial and military purpose. In this paper, it is supposed that seven-meter-class RIB be used as an unmanned target ship for naval training. In order to develop many tactical maneuvering patterns of a target ship, a simple horizontal maneuvering model of a RIB is needed. Therefore, models of speed and yaw rate are constructed as the first-order differential equations based on Lewandowski#s empirical formula for steady turning circle diameter of a conventional planning hull. Some parameters in the models are determined using the results of sea trial tests. Finally, proposed models are validated through the comparison of the simulation result with the sea trial result for a specific scenario. Even though a simple model does not represent the horizontal motion of a RIB precisely, however, it can be used enough to develop tactical trajectory patterns.

A Study on Controller Design to Improve the Driving Performance of the Four Wheel Steering Vehicle (4륜 조향 차량의 주행성능 개선을 위한 제어기 설계에 관한 연구)

  • Sohn, Ju-Han;Choi, Sung-Uk;Lee, Young-Jin;Lee, Jin-Woo;Lee, Kwon-Soon
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2569-2571
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    • 2000
  • In the vehicle steering system, we can consider two methods to steer the vehicle. One is a front wheel steering(FWS), the other is a four wheel steering(4WS). The four wheel steering method has been recently introduced to improve the steering performance. In this paper, we present a design of the four wheel steering controller. First, we constructed the neural network two degree of freedom PID controller to control the 4WS system. Then we compared the performance of conventional PID controller with our proposed controller in terms of yaw rate and side slip velocity. The computer simulation results show that 4WS system controlled by the proposed controller has well driving performances than the other.

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A Study on the Design and Validation of Automatic Pitch Rocker System for Altitude, Speed and Deep Stall Recovery (항공기의 고도, 속도 및 깊은 실속의 회복을 위한 자동회복장치 설계 및 검증에 관한 연구)

  • Kim, Chong-Sup
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.2
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    • pp.240-248
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    • 2009
  • Modem version of supersonic jet fighter aircraft must have been guaranteed appropriate controllability and stability in HAoA(High Angle of Attack). The HAoA flight control law have two parts, one is control law of departure prevention and the other is control law of departure recovery support. The control laws of departure prevention for advanced jet trainer consist of HAoA limiter, roll command limiter and rudder fader. The control laws of departure recovery support are consist of yaw-rate limiter and MPO(Manual Pitch Override) mode. The guideline of pitch rocking using MPO mode is simple, but operating skill of pitch rocking is very difficult by the pilot with inexperience of departure situation. Therefore, automatic deep stall recovery system is necessary. The system called the "Automatic Pitch Rocker System" or APRS, provided a pilot initiated automatic maneuver capable of an aircraft recoveries in situations of deep stall, speed and altitude. This paper addresses the design and validation for APRS to recovery of an deep stall without manual pitch rocking by the pilot. Also, this system is designed to recovery of speed, attitude and altitude after deep stall recovery using ATCS (Automatic Thrust Control System) and autopilot. Finally, this system is verified by real-time pilot evaluation using HQS (Handling Quality Simulator).