• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.999-1010
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• 2003

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulators because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electric lines is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H$\_$$\infty$/ framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

• 한국기계가공학회지
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• 제20권12호
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• pp.107-112
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• 2021

The usage of electric-powered components consisting of several electrical and mechanical parts is continuously increasing in automobiles. Therefore, continuous assessment of the reliability and quality of these electric-powered parts is crucial. In this study, a noise and vibration measurement system for testing and evaluating the different electric-powered parts of automobiles was designed. Further, an FFT analysis was performed on some electric-powered steering assembly test equipment. In the FFT analysis of the noise and vibration signals for each essential fault part, the vibration FFT analysis was significantly compared with the noise analysis. The results showed that the vibration FFT analysis was more effective in determining the reliability and quality of the electric-powered parts.

• 한국정밀공학회지
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• 제26권2호
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• pp.45-53
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• 2009

Today, reduction of $CO_2$ exhaustion gas for global-warming prevention becomes important issues in all industrial fields. Hydraulic systems have been widely used in industrial applications due to high power density and so on. However hydraulic pump is always being operated by engine or electric motor in the conventional hydraulic system. Therefore most of the conventional hydraulic system is not efficient system. Recently, an electro-hydraulic hybrid system, which combines electric and hydraulic technology in a compact unit, can be adapted to a wide variety of force, speed and torque requirements. In the electro-hydraulic hybrid system, hydraulic pump is operated by electric motor only when hydraulic power is needed. Therefore the electro-hydraulic system can reduce the energy consumption drastically when compared to the conventional hydraulic systems. This paper presents a new kind of hydraulic load simulator which is composed of electro-hydraulic hybrid system. Disturbances in the real working condition make the control performance decrease or go bad. QFT controller is designed to eliminate or reduce the disturbance and improve the control performance of the electro-hydraulic load simulator. Experimental results show that the proposed controller is verified to apply for electro-hydraulic hybrid system with varied external disturbances.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.44-51
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• 2008

The performance design and analysis of an electric motor for vehicles is very complicated due to the variety of parameters. This paper presents the design of the BLDC motor for electric air compressor in high voltage(42V) system and compares with the characteristics of IPM, SPM type BLDC motor. Futher, optimal design for the electric motor has been carried out using Equivalent Magnetic Circuit and FEM Modelling. By analyzing the design results, it is found that design parameters for BLDC motor provided an useful tool for vehicles motor design.

• 에너지공학
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• 제23권2호
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• pp.57-61
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• 2014

자동차산업이 해결해야 할 과제로서 석유에너지의 소비증가와, $CO_2$ 배출에의한 지구온난화, 배기가스 배출에 의한 도시부 대기오염 등에 대한 대처가 필요한 시점이다. 이들의 해법으로 시장에서 높은 평가를 받고 있는 전기자동차의 필요성이 대두되고 있다. 본 연구에서는 전기자동차 모터, 배터 리 및 구동모터를 포함한 고전압 핵심부품들의 효율적인 열관리 기술, 배터리 및 구동모터의 열관리 기술 및 개발동향을 알아보고자 한다.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1915-1920
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• 2015

ISO 26262 is an international standard for the functional safety of electric and electronic systems in vehicles, and this standard has become a major issue in the automotive industry. In this paper, a functional safety compliant electronic control unit (ECU) for an electric power steering (EPS) system and a demonstration purposed EPS system are developed, and a software and hardware structure for a safety critical system is presented. EPS is the most recently introduced power steering technology for vehicles, and it can improve driver’s convenience and fuel efficiency. In conformity with the design process specified in ISO 26262, the Automotive Safety Integrity Level (ASIL) of an EPS system is evaluated, and hardware and software are designed based on an asymmetric dual processing unit architecture and an external watchdog. The developed EPS system effectively demonstrates the fault detection and diagnostic functions of a functional safety compliant ECU as well as the basic EPS functions.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.23-30
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• 2010

A detailed circuit level model requires a small sampling time to represent high frequency switching behaviors with proper resolution. The small sampling time leads a large execution time to obtain the system analysis results. As the alternative of the detailed circuit model, an averaged PWM switch model was proposed for the rapid system level analysis. There exists a voltage distortion between the reference and output voltage because of non-ideal switching characteristics, such as the dead-time, diode forward voltage drop and conduction resistance. This paper analyzed causes and effects of the voltage distortion. The average inverter model, which reflecting this voltage distortion, is developed for the rapid and accurate analysis of automotive electric drive system in MATLAB/Simulink environment. The rapidity and accuracy of the proposed inverter model is proved through comparison between simulation and experiment.

• 한국산업융합학회 논문집
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• 제10권1호
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• pp.21-26
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• 2007

As DDI or GDI engine discharges very low heat due to its high thermal efficiency, the heat source is not enough for heating the passenger compartment in cold climate condition. To remedy the heating problem, the conventional HFC-134a automotive air-conditioning system has been attempted to run as a heat pump mode. Futhermore, an auxiliary electric heater of new type was equipped to the heat pump air-conditioning loop as a new approach. Hence, a proto-type heat pump air conditioner has been made and tested to investigate the feasibility of the HFC-134a automobile air-conditioning system that could be worked as a heat pump. The experiment results showed that the sufficient heating capacity could be obtained by adding a heat pump with an new electric type auxiliary heater into the conventional heat core in low temperature condition.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.543-549
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• 2012

Hybrid electric propulsion systems are expected as future primary combat platforms because the systems can supply enough electric power, easily locate components inside vehicles, and maneuver without undesired noise. However, increasing electric/electronic/software usage causes abnormal failure patterns which have not been noticeable in conventional automotive. Recently, the functional safety standard for road vehicles were enacted and vehicle manufacturers request their components which satisfy standardized quality. This research analyzes functional safety standards(IEC 61508 and ISO 26262) and compares the standards for road vehicles with military standards of system safety. Strategies to apply functional safety in the combat hybrid electric vehicle are scrutinized.

• 한국정밀공학회지
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• 제28권11호
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• pp.1265-1271
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• 2011

These days the number of aged and disabled people is increasing rapidly. But most of the disabled or the aged who have the ability to work, want to engage in economic activities and solve social restrictions as well as their bad financial conditions. This paper concerns about the tracking control of an electric wheelchair robot for welfare vehicle where the seat and electric wheelchair are separated and electric wheelchair robot must be autonomously controlled without the help of assistant. So the aged or the disabled people can drive welfare vehicle by himself by adopting this system. Therefore the concept of both an autonomous driving of electric wheelchair and path tracking robots is required in this system. Finally we suggested fuzzy controller in order to control the path tracking of electric wheelchair robot and compared the capability of the proposed controller with conventional PID controller.