• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.525-526
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• 2008

For measuring nonlinear Vehicle Modeling based on 7-Depth Sensor, the neural networks are proposed m adaptive and in realtime. The structure of it is similar to recurrent neural networks; a delayed output as the input and a delayed error between the output of plant and neural networks as a bias input. In addition, we compute the desired value of hidden layer by an optimal method instead of transfering desired values by backpropagation and each weights are updated by RLS(Recursive Least Square). Consequently, this neural networks are not sensitive to initial weights and a learning rate, and have a faster convergence rate than conventional neural networks. This new neural networks is Error Estimated Neural Networks. We can estimate nonlinear models in realtime by the proposed networks and control nonlinear models.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.483-489
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• 2005

Based on a two-degree of freedom vehicle model, this paper investigates ride comfort for a heavy off-road vehicle mounted a nonlinear hydropneumatic spring, which is influenced by nonlinear stiffness and damping characteristics of the hydropneumatic spring. Especially, the damping force is derived by applying H. Blasius formula in modeling process according to the real physical structure of the hydropneumatic spring, and the established model of nonlinear stiffness characteristics have been validated by experiments. Furthermore, the effects of parameter variations of the hydropneumatic spring, such as initial charge pressure and damping coefficient, on body acceleration, suspension deflection and dynamic tire deflection are also investigated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.842-846
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• 1996

Leaf springs are widely used as a major suspension component in many commercial vehicles, such as buses, trucks, etc. They have a complex dynamic behavior due to the geometric nonlinear and the contact mechanism between the leaves. The interface conditions between the leaves play a significant role in the global behavior of the comfort and ride of the vehicle system. The paper concentrates on modeling leaf springs and contact frictions between the leaves using a nonlinear finite element approach. A nonlinear load-displacement hysteresis curve for the leaf spring is simulated and its results are compared with test results.

• 한국철도학회논문집
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• 제3권1호
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• pp.12-18
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• 2000

This paper addresses the experimental study on the nonlinear critical speed and the validity of simple prediction formulation. The experiment on nonlinear critical speed is carried out using roller rigs, which has been impossible on track because of a possibility of an accident. In addition, experiment for a bogie is performed to check the difference in modeling a full railway vehicle and a bogie. It is found that nonlinear critical speed proves to be an inherent phenomenon of a railway vehicle itself and the difference of test results between a full railway vehicle and a bogie is comparatively negligible. Finally. the accuracy of simple prediction formulation for outbreak velocity and response frequency in hunting is investigated.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.29-37
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• 2008

Vehicle stability is a very important subject in vehicle design and control, because vehicle safety is closely dependent upon its dynamic stability. For the vehicle stability analysis, the nonlinear vehicle model of a mid-size car with three DOF - longitudinal, lateral and yaw - is employed. A rigorous method is used to determine the vehicle stability region in plane motion. An algorithm is used to materialize a topology theorem, which enables to find the exact stability region. A stability criterion for the critical cornering is proposed.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.91-99
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• 2006

The diesel Auxiliary Power Unit (APU) for vehicle applications is a complex nonlinear system. For the purpose of this paper presents a dynamic average model of the whole system in an entirely physical way, which accounts for the non-ideal behavior of the diode rectifier, the nonlinear phenomena of generator-rectifier set in an elegant way, and also the dynamics of the dc load and diesel engine. Simulation results show the accuracy of the model. Based on the average model, a simple PI control scheme is proposed for the multivariable system, which includes the steps of model linearization, separate PI controller design with robust tuning rules, stability verification of the overall system by considering it as an uncertain one. Finally it is tested on a detailed switching model and good performances are shown for both set-point following and disturbance rejection.

• 대한기계학회논문집
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• 제11권2호
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• pp.222-233
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• 1987

본 논문에서는 이와 관련하여 전형적인 중장비 구동체계를 대상으로 동적모델 을 유도하는 일련의 과정을 제시하고 구동체계의 효율적 제어를 위한 간략화된 모델을 유도하였다.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3435-3441
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• 2014

차량의 시트 재질로 사용되는 폴리우레탄 폼의 모델링 및 동특성 예측은 승객의 승차감 향상을 위해 매우 중요하다. 본 연구에서는 폴리우레탄 폼의 정특성 시험을 통해 비선형 강성과 점탄성 특성의 시간변수 파라미터를 구하였다. 다항식과 컨벌루션 적분법을 이용하여 폴리우레탄 폼의 비선형 특성과 점탄성 특성을 수학적으로 모델링하였다. 이와 같은 비선형 진동 모델에 대하여 수치적분 방법을 이용하여 시트 바닥 변위에 대한 진동 응답을 계산하였다. 폴리우레탄 폼의 비선형 특성과 점탄성 특성이 진동계에서 미치는 영향을 단순 1자유도계와 인체모델을 이용하여 분석하였다. 결과적으로 폴리우레탄 폼의 점탄성 특성이 승차감을 위한 설계파라미터로 고려되어야 하는 것으로 나타났다.

• International Journal of Aeronautical and Space Sciences
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• 제11권2호
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• pp.69-79
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• 2010

This paper describes the experimental framework for the control system design and validation of a rotorcraft unmanned aerial vehicle (UAV). Our approach follows the general procedure of nonlinear modeling, linear controller design, nonlinear simulation and flight test but uses an indoor-installed multi-camera system, which can provide full 6-degree of freedom (DOF) navigation information with high accuracy, to overcome the limitation of an outdoor flight experiment. In addition, a 3-DOF flying mill is used for the performance validation of the attitude control, which considers the characteristics of the multi-rotor type rotorcraft UAV. Our framework is applied to the design and mathematical modeling of the control system for a quad-rotor UAV, which was selected as the test-bed vehicle, and the controller design using the classical proportional-integral-derivative control method is explained. The experimental results showed that the proposed approach can be viewed as a successful tool in developing the controller of new rotorcraft UAVs with reduced cost and time.

• 한국자동차공학회논문집
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• 제12권3호
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• pp.170-176
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• 2004

MR dampers show highly nonlinear and histeretic dynamic behavior. Therefore, for a vehicle dynamic simulation with MR dampers, this dynamic characteristics should be accurately reflected in the damper model. In this paper, an artificial neural network technique was developed for modeling MR dampers. This MR damper model was successfully verified through a random input forcing test. This MR damper model can be used for semi-active suspension vehicle dynamics and control simulations with practical accuracy.