• Title, Summary, Keyword: Loop Wheel

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A Study on the AWS (All Wheel Steering) ECU Test considering Requirement for Behavior of Bi-modal Tram (바이모달 트램의 거동을 요구사항으로 고려한 전차를 조향 시스템 테스트에 관한 연구)

  • Lee, Jin-Hee;Park, Tae-Won;Lee, Soo-Ho;Jung, Ki-Hyun;Choi, Kyung-Hee;Moon, Kyeong-Ho
    • Proceedings of the KSR Conference
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    • pp.229-238
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    • 2009
  • In this paper, AWS ECU test method, which is considering behavior of a Bi-modal tram, is described. In order to evaluate the performance of an electronic automotive ECU, the method which combines HILS (Hardware In the Loop Simulation) and RBT (Requirement Based Testing) is introduced. HILS is the method to predict the behavior of a vehicle adopting an ECU. The behavior of a Bi-modal tram can be analyzed by using the vehicle dynamic model. Requirement Based Testing compare the outputs of a real system with a virtual electronic unit (oracle) which created by the requirements. Rear axles of the Bi-modal tram are independently controlled by two AWS ECU. Especially, swing out can happen when an articulated vehicle is operated in the curved road. Therefore dynamic behaviour of a Bi-modal tram is considered at this situation. Through this study, the reliability of ECU can be verified economically and safely using the proposed test method before conducting the track test.

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Identification of Optimal Control Parameters for a Pneumatic Active Engine Mount System (공압식 능동형 엔진마운트시스템의 최적 제어매개변수 식별)

  • Kim, Il-Jo;Lee, Jae-Cheon;Choi, Jae-Yong;Kim, Jeong-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.2
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    • pp.30-37
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    • 2012
  • Pneumatic Active Engine Mount(PAEM) with open-loop control system has been developed to reduce the transmission of the idle-shake vibration induced by engine effectively and economically. A solenoid valve installed between PAEM and vacuum tank is on-off switched by the Pulse Width Modulate(PWM) control signal to decrease the dynamic stiffness of the engine mount. This paper presents the methodology to identify the optimal values of control parameters of a PAEM, i.e, turn-on timing and duty ratio of PWM signal for 6 different idle driving conditions. A scanning algorithm was first applied to the vehicle test to obtain the approximate optimal control parameters minimizing the vibration at front seat rail and at steering wheel. Then the PAEM system identification was fulfilled to find accurate optimal control parameters by using multi-layer neural networks of Levenberg-Marquardt algorithm with vehicle test data.

Design of Quantitative Feedback Control System for the Three Axes Hydraulic Road Simulator (3축 유압 도로 시뮬레이터의 정량적 피드백 제어 시스템 설계)

  • Kim, Jin-Wan;Xuan, Dong-Ji;Kim, Young-Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.3
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    • pp.280-289
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    • 2008
  • This paper presents design of the quantitative feedback control system of the three axes hydraulic road simulator with respect to the dummy wheel for uncertain multiple input-output(MIMO) feedback systems. This simulator has the uncertain parameters such as fluid compressibility, fluid leakage, electrical servo components and nonlinear mechanical connections. This works have reproduced the random input signal to implement the real road vibration's data in the lab. The replaced $m^2$ MISO equivalent control systems satisfied the design specifications of the original $m^*m$ MIMO control system and developed the mathematical method using quantitative feedback theory based on schauder's fixed point theorem. This control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) having the minimum bandwidth for parameters of uncertain plant. The efficacy of the designed controller is verified through the dynamic simulation with combined hydraulic model and Adams simulator model. The Matlab simulation results to connect with Adams simulator model show that the proposed control technique works well under uncertain hydraulic plant system. The designed control system has satisfied robust performance with stability bounds, tracking bounds and disturbance. The Hydraulic road simulator consists of the specimen, hydraulic pump, servo valve, hydraulic actuator and its control equipments

An Investigation into Coordinated Control of 4-wheel Independent Brakes and Active Roll Control System for Vehicle Stability (차량 안정성 향상을 위한 ESC와 ARS의 통합 샤시 제어 알고리즘 개발)

  • Her, Hyundong;Yi, Kyongsu;Suh, Jeeyoon;Kim, Chongkap
    • Journal of Auto-vehicle Safety Association
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    • v.5 no.1
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    • pp.37-43
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    • 2013
  • This paper describes an investigation into coordinated control of electronic stability control (ESC) and active roll control system (ARS). The coordinated control is suggested to improve the vehicle stability and agility features by yaw rate control. The proposed integrated chassis control algorithm consists of a supervisor, control algorithms, and a coordinator. The supervisor monitors the vehicle status and determines desired vehicle motions such as a desired yaw rate and desired roll motion based on control modes to improve vehicle stability. According to the corresponding the desired vehicle dynamics, the control algorithm calculated a desired yaw moment and desired roll moment, respectively. Based on the desired yaw moment and the desired roll moment, the coordinator determines the brake pressures and the ARC motor torques based on control strategies. Closed loop simulations with a driver-vehicle-controller system were conducted to investigate the performance of the proposed control strategy using CarSim vehicle dynamics software and the integrated controller coded using Matlab/Simulink.

Research on Development of Turbo-generator with Partial Admission Nozzle for Supercritical CO2 Power Generation (부분 유입 노즐을 적용한 초임계 이산화탄소 발전용 초고속 터보발전기 개발 연구)

  • Cho, Junhyun;Shin, Hyung-ki;Kang, Young-Seok;Kim, Byunghui;Lee, Gilbong;Baik, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.4
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    • pp.293-301
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    • 2017
  • A Sub-kWe small-scale experimental test loop was manufactured to investigate characteristics of the supercritical carbon dioxide power cycle. A high-speed turbo-generator was also designed and manufactured. The designed rotational speed of this turbo-generator was 200,000 rpm. Because of the low expansion ratio through the turbine and low mass flowrate, the rotational speed of the turbo-generator was high. Therefore, it was difficult to select the rotating parts and design the turbine wheel, axial force balance and rotor dynamics in the lab-scale experimental test loop. Using only one channel of the nozzle, the partial admission method was adapted to reduce the rotational speed of the rotor. This was the world's first approach to the supercritical carbon dioxide turbo-generator. A cold-run test using nitrogen gas under an atmospheric condition was conducted to observe the effect of the partial admission nozzle on the rotor dynamics. The vibration level of the rotor was obtained using a gap sensor, and the results showed that the effect of the partial admission nozzle on the rotor dynamics was allowable.

Two Axis Attitude Control System Design of Momentum Biased Satellite (모멘텀 바이어스 인공위성의 2축 자세제어 시스템 설계)

  • Lee, Seung-U;Seo, Hyeon-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.4
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    • pp.40-46
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    • 2006
  • It is required to develop a highly reliable attitude & orbit control system of satellite that is less expensive as the technology of satellite design & integration is recently matured dramatically. To accomodate this kind of needs, the two axis attitude control method for wheel-based momentum-biased satellite system whose momentum bias vector points to a certain direction(sun direction), is developed using simple but reliable sensors and actuator: three axis magnetometer and coarse sun sensor are used as sensors, and magnetic torque bars are used as actuator. Classical PD type controller design methodologies are applied on a satellite system for the two axis control with the proper assumptions. Nonlinear simulation results are included to demonstrate the long term stability and the performance of closed-loop system design results.

Development of Pump-Drive Turbine with Hydrostatic Bearing for Supercritical CO2 Power Cycle Application (정압 베어링을 적용한 초임계 CO2 발전용 펌프-구동 터빈 개발)

  • Lee, Donghyun;Kim, Byungock;Park, Mooryong;Yoon, Euisoo
    • Tribology and Lubricants
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    • v.36 no.3
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    • pp.153-160
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    • 2020
  • In this paper, we present a hydrostatic bearing design and rotordynamic analysis of a pump-and-drive turbine module for a 250-kW supercritical CO2 cycle application. The pump-and-drive turbine module consists of the pump and turbine wheel, assembled to a shaft supported by two hydrostatic radial and thrust bearings. The rated speed is 21,000 rpm and the rated power is 143 kW. For the bearing operation, we use high-pressure CO2 as the lubricant, which is supplied to the bearing through the orifice restrictor. We calculate the bearing stiffness and flow rate for various orifice diameters, and then select the diameter that provides the maximum bearing stiffness. We also conduct a rotordynamic analysis based on the design parameters of the pump-and-drive turbine module. The predicted Campbell diagram shows that there is no critical speed below the rated speed, owing to the high stiffness of the bearings. Furthermore, the predicted damping ratio indicates that there is no unstable mode. We conduct the operating tests for the pump and drive turbine modules within the supercritical CO2 cycle test loop. The pressurized CO2, at a temperature of 136℃, is supplied to the turbine and we monitor the shaft vibration during the test. The test results show that there is no critical speed below the rated speed, and the shaft vibration is controlled to below 3 ㎛.

Development and Application of the High Speed Weigh-in-motion for Overweight Enforcement (고속축하중측정시스템 개발과 과적단속시스템 적용방안 연구)

  • Kwon, Soon-Min;Suh, Young-Chan
    • International Journal of Highway Engineering
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    • v.11 no.4
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    • pp.69-78
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    • 2009
  • Korea has achieved significant economic growth with building the Gyeongbu Expressway. As the number of new road construction projects has decreased, it becomes more important to maintain optimal status of the current road networks. One of the best ways to accomplish it is weight enforcement as active control measure of traffic load. This study is to develop High-speed Weigh-in-motion System in order to enhance efficiency of weight enforcement, and to analyze patterns of overloaded trucks on highways through the system. Furthermore, it is to review possibilities of developing overweight control system with application of the HS-WIM system. The HS-WIM system developed by this study consists of two sets of an axle load sensor, a loop sensor and a wandering sensor on each lane. A wandering sensor detects whether a travelling vehicle is off the lane or not with the function of checking the location of tire imprint. The sensor of the WIM system has better function of classifying types of vehicles than other existing systems by detecting wheel distance and tire type such as single or dual tire. As a result, its measurement errors regarding 12 types of vehicle classification are very low, which is an advantage of the sensor. The verification tests of the system under all conditions showed that the mean measurement errors of axle weight and gross axle weight were within 15 percent and 7 percent respectively. According to the WIM rate standard of the COST-323, the WIM system of this study is ranked at B(10). It means the system is appropriate for the purpose of design, maintenance and valuation of road infrastructure. The WIM system in testing a 5-axle cargo truck, the most frequently overloaded vehicle among 12 types of vehicles, is ranked at A(5) which means the system is available to control overloaded vehicles. In this case, the measurement errors of axle load and gross axle load were within 8 percent and 5 percent respectively. Weight analysis of all types of vehicles on highways showed that the most frequently overloaded vehicles were type 5, 6, 7 and 12 among 12 vehicle types. As a result, it is necessary to use more effective overweight enforcement system for vehicles which are seriously overloaded due to their lift axles. Traffic volume data depending upon vehicle types is basic information for road design and construction, maintenance, analysis of traffic flow, road policies as well as research.

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