• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.741-745
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• 2001

Reliability and safety of steer-by-wire concepts can be achieved by redundant designs. This paper discusses the design of a fault tolerant concept for a force feedback actuator with a standard three-phase PMSM. In contrast to usual drives, the phases of the machine are separated electrically. This design allows driving the machine with two instead of three phases in case of a fault. A superimposed torque controller adjusts the influence of fault currents and torque harmonics in two-phase operation and guarantees smooth torque at the steering wheel

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.185-188
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• 2005

본 논문에서 신경망을 이용한 자계기반 자율주행 시스템의 조향 제어기 설계를 제안한다. 자율주행시스템에서 가장 중요한 핵심요소는 자계토로상의 센서의 현재위치를 파악하고 주행하는 것이다. 먼저 자계도로상의 현재위치를 파악하기 위한 방법으로, 첫 번째 자기쌍극자 모델식이 센서에서 측정된 자계와 일치함을 보였다. 두 번째 Peak Mapping법을 이용하여 외란으로 작용하는 지자계 성분을 제거할 수 있음을 입증하였다. 세 번째로 신경망을 이용하여 높이성분($B_{z}$)가 변하더라도 정확한 거리가 계측됨을 확인하였다. 따라서 신경망을 이용하면 소량의 메모리를 사용할 수 있으므로 실제 시스템에서 경제적인 효과를 볼 수 있고, 정확한 거리를 계측하므로 경로를 이탈하지 않고 자율주행이 가능한 시스템을 설계하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.347-354
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• 2000

This paper presents performance characteristics of a semi-active suspension featuring continuously variable ER (electro-rheological) dampers. These are evaluated through the field test of a passeng er car. Four ER dampers (two for front and two for rear part) are manufactured and their field-dependent damping properties are experimentally investigated. The damping force responses to step input fields are also identified by employing small size of high voltage amplifiers which are made adaptable to the field test. A skyhook controller considering the vertical, pitch and roll motions is formulated and incorporated with a car to be tested. The field test is then undertaken in order to evaluate both comfortability and steering stability showing bump, dive and squat responses.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.369-374
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• 2007

This paper presents yaw vibration control performances of railway vehicle featuring controllable magnetorheological damper. A cylindrical type of MR damper is devised and its damping force is evaluated by considering fluid resistance and MR effect. Design parameters are determined to achieve desired damping force level. The MR damper model is then incorporated with the governing equations of motion of the railway vehicle which includes vehicle body, bogie and wheel-set. Subsequently, computer simulation of vibration control via proportional-integral-derivative (PID) controller is performed using Matlab. Various control performances are demonstrated under external excitation by creep force between wheel and rail.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1253-1263
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• 2002

The control system design and modeling of an unmanned vehicle by means of a new concept for better performance through a tole-operation system is suggested by sensor fusion. But, the control of a real vehicle is very difficult, because the system identification of the vehicle is hard to find the unknown factors and the disturbances of the experimental environment. For the longitudinal and lateral controls, the traction system and steering system models are set up and a tuning method to find the gain of the controller by experiments is presented. In this research, mechanical and electronic parts are implemented to operate the unmanned vehicle and data reconstruction method of information about the environment data coming from several sensors is presented by data plot for the vehicle navigation. This paper focuses on the integration of tole-operated unmanned vehicle. This vehicle mainly controlled lateral and longitudinal directions with actuators for controlling vehicle movement and sensors for the closed-loop controlled system.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.45-54
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• 1993

Monitoring processor in a circuit switched network is considered. Monitoring processor monitors communication links offers a grade of service in each link to controller. Such an information is useful for an effective maintenance of system. Two links with asymmetric system parameters and multi-symmetric links are respectively considered. Each links is to be an independent M /M/ 1/ 1/ type. Markov modeling technique is used to represent a model of monitoring processor with FCFS steering protocol. Performance measures considered are ratio of monitored jobs in each link, availability of minitoring processor and throughput of virtual processor in each link. The value of the performance meausres are compared with existing and simulation results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1460-1463
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• 2005

In this paper, analysis of magnetic marker for autonomous vehicle guidance system using 3-axis magnetic sensor propose. Position sensing is an important an estimation system of vehicle position and orientation on magnetic lane, which is a parameter of the steering controller for automated lane following is described. To verify that the magnetic dipole model could be applied to a magnetic unit paved in roadway, the analysis of the data 3-axis magnetic field measured experimentally.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.161.1-161
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• 2001

Tire roller is one of the most useful machines for the road constructions site. In this research, we are trying to develop tire roller which is operated by hydraulic transmission system instead of mechanical one. Now, we are trying to design the controller of tire roller in order to improve performance. Our present system model is somewhat different from the actual experimental results. Therefore we would like to develop new accurate modeling through ARX model by system identification method with random inputs. In this paper, we applied it to the steering system only. Later we will apply it to the traction system and expand to the whole tire roller system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.180.1-180
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• 2001

In the autonomous vehicle, the reference lane is continually detected by machine vision system. And then the vehicle is steered to follow the reference yaw rates which are generated by the deviations of lateral distance and the yaw angle between the vehicle and the reference lane. To cope with the steering delay and the side-slip of vehicle, PI controller is introduced for the yaw rate feedback. And it is tuned by the simulation that the vehicle is modeled as 2 DOF verified by the results of the actual vehicle test. The lateral control algorithm by the yaw rate feedback has good performances of lane tracking and passenger comfort.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.524-532
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• 2008

This paper presents yaw vibration control performances of railway vehicle featuring controllable magnetorheological damper. A cylindrical type of MR damper is devised and its damping force is evaluated by considering fluid resistance and MR effect. Design parameters are determined to achieve desired damping force level. The MR damper model is then incorporated with the governing equations of motion of the railway vehicle which includes vehicle body, bogie and wheel-set. Subsequently, computer simulation of vibration control via proportional-integral-derivative(PID) controller is performed using Matlab. Various control performances are demonstrated under external excitation by creep force between wheel and rail.