• 동력기계공학회지
• /
• 제10권1호
• /
• pp.12-18
• /
• 2006

A three-degree of freedom model of intake system was contrived and investigated in various ways for the purpose of the amelioration of the volumetric efficiency in a low and transient engine speed for a multi cylinder diesel engine. The basic concept beyond this model started from the theory that each degree of freedom model has volumetric efficiency peak as many as its number of the degree of freedom. The volumetric efficiency affects significantly to the engine performance; torque characteristics, fuel economy and emission level. For commercial vehicles and stationary engines, the engine is designed so as to produce their best performance near the normal engine speeds, thus the low engine speed area has a tendency of poor volumetric efficiency. The aim of this study was highlighted on the amelioration of volumetric efficiency of low engine speed area in a multi cylinder diesel engine matched with an additional Helmholtz resonator. By the use of VIS(variable induction system) volumetric efficiency at low engine speed range was significantly improved. The availability of control by combination of VIS and CIS(conventional induction system) will be proposed as a variable induction system that would be an appropriate model for amelioration of the volumetric efficiency at low engine speed.

• 대한기계학회논문집
• /
• 제10권3호
• /
• pp.305-315
• /
• 1986

본 연구에서는 가변 기통 엔진의 동특성을 규명하기 위해 세곳으로 지지되는 직렬 4기통 디이젤 엔진에 대한 3자유도 모델을 설정하였고, 이 모델에서 각 마운트의 위치와 경사각 및 방진고무의 크기를 변경시킬 때의 최적화 문제를 컴퓨터 시뮬레이션 으로 고찰하였다.

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2000년도 추계종합학술대회논문집
• /
• pp.193-196
• /
• 2000

ln this paper, we consider to apply of 2-DOF (Degree of Freedom) PID controller at D.C servo motor system. Many control system use I-PD, PIB control system. but the position control system have difficulty in controling variable load and changing parameter We propose neural network 2-DOF PID control system having feature for removal disturbrances and tracking function in the target value point.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.528-531
• /
• 1997

This paper deals with the kinematic and dynamic modeling of a 3 degree-of-freedom redundantly actuated mobile robot for the purpose of analysis and control. Each wheel is driven by two motors for steering and driving. Therefore, the system becomes force-redundant since the number of input variable is greater than the number of output variable. The kinematic and dynamic models in terms of three independent joint variables are derived. Also, a load distribution method to determine the input loads is introduced. Finally we demonstrate the feasibility of the proposed algorithms through simulation.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2001년도 춘계종합학술대회
• /
• pp.395-398
• /
• 2001

본 논문에서는 직류 서보 전동기를 구동원으로 하는 위치 제어계에서 부하변동에 따른 파라메타 변화, 외란 둥에 강인한 2자유도 PID 제어기의 설계법을 제시하여 신경망으로 2자유도 PID 제어기를 구성하였다. 이 제어기의 계수들이 기동시나 계 응답의 변동시 신경망 역전파 알고리즘(Back-Propagation Algorithm)에 의해서도 수성 되도록 하였다. 그리고 이것을 실제의 위치 제어계에 적용하여 실험을 통해 그 성능을 검증하였다.

• 대한기계학회논문집A
• /
• 제22권3호
• /
• pp.504-518
• /
• 1998

Degree-Of-Freedom(DOF) for most power transmission system varies according to the operation status which consists of friction elements to change the power flow or to adjust the speed ratio such as clutches, brakes or one-way clutches. To simulate the dynamic characteristics of automatic power transmission system which is a typical example of such a variable DOF systems, many sets of governing equations and complicated phase decision routines are necessary. In this paper dynamic constraint theorem is derived explaining the torque transmission characteristics during the clutch engagement process and a robust stable algorithm is developed describing this phase transition phenomenon effectively by introducing the concept of direct torque and virtual damping. Finally, applying this algorithm to a passenger car automatic transmission gear consisting of several friction elements, an efficient simulation methods for such a complex system will be suggested that is very simple and systematic.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.229-234
• /
• 2001

A practical and effective semi-active on-off control law is developed for vibration attenuation of a natural, multi-degree-of-freedom suspension system, when its operational response mode is available. It does not need the accurate system parameters and dynamics of semi-active actuator. It reduces the total vibratory energy of the system including the work done by external disturbances and the maximum energy dissipation direction of the semi-active control device is tuned to the operational response mode of the structure. The effectiveness of the control law is illustrated with a three degree-of-freedom excavator cabin model.

• 한국자동차공학회논문집
• /
• 제8권6호
• /
• pp.142-155
• /
• 2000

A MIMO model reference control scheme incorporating the variable structure theory for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of continuous-time nonlinear dynamics with known or unknown uncertainties. The scheme employs an neural network to identify the plant systems, where the neural network estimates the nonlinear dynamics of the plant. By the Lyapunov direct method, 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 and it is not necessary to know the exact structure of the system. With the resulting identification model which contains the neural networks, it does not need higher degrees of freedom vehicle model than 3 degree of freedom model. Th proposed scheme is applied to the active four wheel system and shows the validity is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the reduction of yaw rate overshoot of a typical mid-size car improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response and smaller side angle than the 2WS case.

• 대한기계학회논문집
• /
• 제18권8호
• /
• pp.2088-2100
• /
• 1994

Considerable attention has been given to controller designs that utilize the variable structure system theory in order to achieve robust tracking performance of robotic manipulators subjected to parameter variations and extraneous disturbances. However, the theory has not had wide spread acceptance in practical control engineering community due mainly to the worry of chattering which is inherently ever-existing in the variable structure system. This paper presents a novel type of fuzzy-sliding mode controller to alleviate the chattering problem. A sliding mode controller for robust robot control is firstly synthesized with an assumption that the imposed system uncertainties satisfy matching conditions so that certain deterministic performances can parameters and control rules are obtained from a relation between predetermined sliding surfaces and representative points in the error state space. A two degree-of-freedom robotic manipulator subjected to a variable payload and a torque disturbance is considered in order to demonstrate superior tracking performance accrued from the proposed methodology.

• 동력기계공학회지
• /
• 제4권1호
• /
• pp.68-73
• /
• 2000

A mixed degree finite element solutions using hierarchical elements are investigated for convergences on a 2-D simple cases. Elements are generated block by block and each block is assigned an arbitrary solution degree. The numerical study showed that a well constructed blocks can increase the convergence and accuracy of finite element solutions. Also, it has been found that for higher order elements, the convergence trends can be deteriorated for smaller mesh sizes. A procedure for a variable fixed boundary condition has been included.