• International Journal of Automotive Technology
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• 제1권1호
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• pp.48-55
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• 2000

Two major roles of the traction control system (TCS) are to guarantee the acceleration performance and directional stability even in extreme road conditions, under which average drivers may not control the car properly. Commercial TCSs use experiential methods such as lookup table and gain-scheduling to achieve proper performance under various road and vehicle conditions. This paper proposes a new slip controller which uses the brake and the throttle actuator simultaneously. To avoid measurement problems and to get a simple structure, the brake controller and the throttle controller are designed using Lyapunov redesign method and multiple sliding mode control respectively. Through the hybrid use of brake and throttle controllers, the vehicle is insensitive to the variation of the vehicle mass, brake gain and road condition and can achieve the required acceleration performance. The proposed method is validated with simulations based on 15 DOF passenger car model.

• 대한기계학회논문집A
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• 제27권5호
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• pp.666-672
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• 2003

This paper presents a design of the controller for vehicle lateral dynamics using active yaw moment. Vehicle lateral motion is incorporated with directional controllability and stability. These are conflicting each other from the view of vehicle handling performance. To compromise the trade-off between these two aspects, we suggest a new control algorithm based on the sliding mode with time-varying switching surface according to the body side slip angle. The controller can deal with the nonlinear region in vehicle driving condition and be robust to the parameter uncertainties in the plant model. Control performance is evaluated from the simulation for the vehicle of real parameters on the road with various tire-road frictions.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.175-180
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• 2002

In order to satisfy the requirements of time reduction and cost saving for development of electronic control systems(ECU) in automotive industry, the applications of a standardized real-time operating system(RTOS) and a communication protocol to ECUs are increased. In this study, a body control module(BCM) that employs OSEK/VDX(open system and corresponding interfaces for automotive electronics/vehicle distributed executive) OS tour the RTOS and a controller area network(CAN) fur the communication protocol is designed, and the performances of the system are evaluated. The BCM controls doors, mirrors, and windows of the vehicle through the in-vehicle network. To identify all the transmitted and received control messages, a PC connected with the CAN communication protocol behaves as a CAN bus emulator. The control system based upon in-vehicle network improves the system stability and reduces the number of wiring harness. Furthermore it is easy to maintain and simple to add new features because the system is designed based on the standards of RTOS and communication protocol.

• International Journal of Ocean System Engineering
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• 제1권3호
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• pp.120-135
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• 2011

This paper proposes a model based trajectory tracking control scheme for under-actuated underwater robotic vehicles. The difficulty in stabilizing a non-linear system using smooth static state feedback law means that the design of a feedback controller for an under-actuated system is somewhat challenging. A necessary condition for the asymptotic stability of an under-actuated vehicle about a single equilibrium is that its gravitational field has nonzero elements corresponding to non-actuated dynamics. To overcome this condition, we propose a continuous time-varying control law based on the direct estimation of vehicle dynamic variables such as inertia, damping and Coriolis & centripetal terms. This can work satisfactorily under commonly encountered uncertainties such as an ocean current and parameter variations. The proposed control law cancels the non-linearities in the vehicle dynamics by introducing non-linear elements in the input side. Knowledge of the bounds on uncertain terms is not required and it is conceptually simple and easy to implement. The controller parameter values are designed using the Taguchi robust design approach and the control law is verified analytically to be robust under uncertainties, including external disturbances and current. A comparison of the controller performance with that of a linear proportional-integral-derivative (PID) controller and sliding mode controller are also provided.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.174.1-174
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• 2001

The role of suspension system in tracked vehicles cannot be overestimated because the driving and running conditions of such vehicles are very severe. It reduces the vibration and shock which are generated by road profile in running condition. As the tracked vehicle's running speed increases, more undesired vibrations can be generated by road profile particularly in the situation of field running. Because, the excessive vibration can harm the operation ability of crewmen and stability of complex equipments, the maximum running speed is limited. In this study, to improve the performance of the tracked vehicle system, we examined the feasibility of using the active preview control for the tracked vehicle´s suspension system. First, we developed ...

• 한국지능시스템학회논문지
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• 제7권4호
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• pp.29-39
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• 1997

A discrete model reference control scheme for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of discrete time nonlinar dynamics. The schmen employs a neural network to identify the plan systems, wher the neural network estimates the nonlinear dynamics of the plant. The algorithm is proven to be globally stable, with tracking errors converging to the neighborhood of zero. The merits of this scheme is that the global system stability is guaranteed. Whith thd resulting identification model which contains the neural networks, the parameters of controller are adjusted. The proposed scheme is applied to the vehicle active four wheel system and shows the validity and effectiveness through simulation. The three-degree-of freedom vehicle handling model is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the yaw rate overshoot reduction of a typical mid-size car is improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response andl smaller side slip angle than the 2WS case.

• 대한교통학회지
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• 제26권3호
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• pp.179-186
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• 2008

교통류의 안정성을 깨지 않음과 동시에 생산성을 저하시키지 않는 적절한 교통류 관리 방안이 필요하다. 지금까지 기존 지능형교통시스템(ITS: Intelligent Transportation System)에 의한 교통류관리에서는, 이러한 개념의 교통류 관리 방안을 명시적으로 다루지 못하였다. u-T(Ubiquitous Transportation) 시스템 환경 하에서, 개별차량 위치, 속도 등 미세한 데이터 수집이 가능해 지며, 이러한 개별차량 위치 데이터에 의해 기존 ITS 환경에서는 수집 불가능했던 밀도 산정이 가능해 진다. 또한 V2I(Vehicle-to-Infra), V2V (Vehicle- to-Vehicle) 등 양방통신이 가능해 짐에 따라 개별차량 혹은 차량군 단위의 미세 제어와 개별차량 단위의 미세 대응이 가능해 진다. 본 논문에서는, 이러한 u-T의 수집 데이터와 통신환경을 기반으로, 교통류가 불안정해 사고 잠재력이 커지고 결국 교통류가 와해되어 생산성이 저하되는 것을 예방하는 예방차원의 교통류 관리 방안을 제시하였다. 이것을 실현하기 위한 적정 속도, 적정 차두간격을 그린쉴드 모형에 기반하여 산정하였는데, 제반 교통류 모형을 비교 평가하여 적정 모형을 선택하는 연구도 향후 수행되어야 할 것으로 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권2호
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• pp.159-165
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• 2015

Motion control schemes are generally classified into three categories (point stabilization, trajectory tracking, and path following). This paper deals with the problem which is associated with the initial deployment of a group of Unmanned Surface Vehicle (USVs) and corresponding point stabilization. To keep the formation of a group of USVs, it is necessary to set the relationship between each vehicle. A forcing functions such as potential fields are designed to keep the formation and a graph Laplacian is used to represent the connectivity between vehicle. In case of fixed topology of the graph representing the communication between the vehicles, the graph Laplacian is assumed constant. However the graph topologies are allowed to change as the vehicles move, and the system dynamics become discontinuous in nature because the graph Laplacian changes as time passes. To check the stability in the stage of deployment, the system is modeled with Kronecker algebra notation. Filippov's calculus of differential equations with discontinuous right hand sides is then used to formally characterize the behavior of USVs. The stability of the system is analyzed with Lyapunov's stability theory and LaSalle's invariance principle, and the validity is shown by checking the variation of state norm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1389-1394
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• 2010

This paper describes the evaluation of structural integrity and dynamic characteristic of inertial load test equipments for performance test of railway vehicle propulsion control system. The propulsion control system of railway vehicle has to be confirmed of safety and reliability prior to it's application. Therefore, inertial load test equipments were designed through theoretical equation for performance test of propulsion control system. The structural analysis of inertial load test equipments was conducted using Ansys v11.0 and it's dynamic characteristic was evaluated the designed using Adams. The results showed that the structural integrity of inertial load test equipment was satisfied with a safety factor of 10.2. Also, the structural stability was proved by maximum dynamic displacement of 0.82mm.

• 동력기계공학회지
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• 제8권4호
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• pp.57-63
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• 2004

Conventionally, 2WS is used for vehicle steering, which can only steering front wheel. In case of trying to high speed lane change or cornering through this kind of vehicle equipped 2WS, it may occur much of Yaw moment. On the other hand, 4WS makes decreasing of Yawing Moment, outstandingly, so it is possible to support vehicle movement stable. And conventional ABS and TCS can only possible to control the longitudinal movement of braking equipment and drive which can only available to control of longitudinal direction. There after new braking system ESP was developed, which controls both of longitudinal and lateral, with adding of the function of controlling Active Yaw Moment. On this paper, we show about not only designing of improved braking and steering system through establishing of the integrated control system design of 4WS and ESP but also designing of the system contribute to precautious for advanced vehicle stability problem.