• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.871-875
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• 1996

The Output feedback linear quadratic regulator control is applied to the design of active suspension system using 7 DOF full car model. The performance index reflects the vehicle vertical movement, pitch and roll motion, and minimization of suspension stroke displacements in the rattle space. The elements of gain matrix are approximately decoupled so that each suspension requires only local information to generate the control force. The simulation results indicates that the output feedback LQ controller is more effective than purely passive or full state feedback active LQ controllers in following the road profile at the low frequency range and suppressing the road disturbance at the high frequency ranges.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.168-173
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• 2002

The durability test, along with the crashworthiness test, requires the most time and expense in the vehicle development process. The durability design using CAE tools reduces the time required for both the durability test and actual vehicle production. Existing dynamic stress analyses designed fir the analysis of vehicle fatigue mainly calculate the dynamic stress history and fatigue after performing dynamic analysis and stress analysis with relevant software applications and then superpositioning the dynamic load history and stress influence coefficient at each joint. This approach is a complex process, taking into account the flexibility of the parts. It is, however, incapable of giving accurate consideration to the contacts between components, the non-linearity of materials, and tire-road surface interactions. This approach also requires that the analysts have an expertise in software applications of various kinds or an expert in each area must perform the analysis. This requires as a great deal of manpower and time. In order to complement the existing approaches for dynamic stress analysis, this study aims at the following: (1) to suggest the simple and accurate analysis technique which is capable of producing all the possible necessary results; (2) to reduce dramatically the time and manpower needed to construct a model designed to analyze dynamics, quasi-static stress, and fatigue; and (3) to enable an accurate analysis of fatigue by improving the accuracy of dynamic stress. we verify the presented analysis method through durability evaluation of the knuckle of passenger car.

• 한국산학기술학회논문지
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• 제19권9호
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• pp.84-90
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• 2018

철도차량의 거동을 해석하기 위하여 다물체 동역학 모델을 구성함에 있어 현가시스템을 구성하는 스프링, 댐퍼와 같은 현가요소에 대한 스프링강성이나 감쇠계수와 같은 물성치 파악은 매우 중요하다. 그 중 1차, 2차 현가시스템에 주로 활용되고 있는 코일스프링에 대한 동역학 모델을 구성함에 있어 축방향 강성은 도면이나 설계자료에 명확하게 명시되어 있지만 횡방향에 대한 물성은 명시되어 있지 않아 동역학 해석 모델 구성에 어려움을 안고 있다. 따라서 본 논문에서는 철도차량의 현가시스템에 폭 넓게 적용되고 있는 코일스프링에 대한 횡강성을 해석하기 위한 모델에 대하여 검토하고자 한다. 코일스프링 시료에 대한 횡강성을 해석하고자 유한요소해석 방법을 수행하였고 Krettek와 Sobczak의 코일스프링 횡강성 해석모델을 적용하여 수치해석을 수행하였다. 그리고 코일스프링 시료를 대상으로 횡강성 특성시험을 수행하여 해석모델과의 적합성을 검토하였다. 시험결과와 비교한 결과, Krettek와 Sobczak의 코일스프링 횡강성 해석모델을 적용하고 보정계수를 수정한 결과가 시험결과에 근사한 결과를 얻을 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.69-74
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• 2006

It is known that the various noise sources which are engine, transmission, tire, intake system, etc exist at vehicle driving status. Specially noises which cannot be expected by a driver induce unpleasantness to all passengers. These noises are difficult to distinguish noise sources or specifications because of too many vehicle parts. Therefore in this paper, study on abnormal noise of bush on suspension system is performed by the measurement and analysis of the noises of bushings that are generated artificially. The measured noises are analyzed by two points-view of spectrum and sound quality. Finally, it is shown that the noise sources of bushings on the suspension system which are the pillow ball joint bush of a control arm and the rubber bush of a lower arm could be distinguished by the spectrum distribution and a index value based on tonality.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.633-641
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• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.

• 동력기계공학회지
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• 제6권2호
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• pp.33-39
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• 2002

Commercial vehicles are mostly subjected to relatively rougher ground environment than passenger vehicles. Many driver's seats of commercial vehicles have suspension system with spring and dampers. Then, impact or vibrative forces transmitted from the vehicle to the driver can be attenuated. This study deals with a ride evaluation method using sky-hook control algorithm for the suspension dampers. Vibration amplitude transmissibilities were compared between passive dampers and semi-active dampers with sky-hook control method.

• 동력기계공학회지
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• 제3권3호
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• pp.91-96
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• 1999

This study is about the design and analysis ot a suspension damper for truck driver's seat to improve the ride comfort. Trucks are usually subjected to hostile driving environments. Therefore, many truck driver's seat have suspension seats to isolate the vibration from the cab floor panel. Because the vehicle suspension system can reduce the primary vibration from the ground, only low frequency vibration can be transmitted to the driver's seat. But, this low frequency vibration can be harmful to the driver. The seat damper is very critical element to improve the ride comfort for the driver. In this study, a four-stage damper is designed and analyzed for the vibration capability. The damping coefficient of this damper can lie manually controlled in response to the road and driving environment.

• 한국자동차공학회논문집
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• 제5권2호
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• pp.31-41
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• 1997

Equations of motion for a 7 DOF full car model is developed in detail and used for the design of LQR based active suspension system. The frequency response to road disturbance input and the motion of a car passing unequal bumps were used to analyzed the dynamic characteristics of the 7 DOF full car with passive or active suspensions. The resulting linear equations of motion may be usefull in designing other types of active suspension.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.369-374
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• 2004

Nowadays, the more speedy and functional railway vehicles are required by customers, the more broad boundary conitions of train's running are present. At this condtion, it is difficult for the traditional concept of suspension system which has the constant characteristics dependant on the running condition to meet the advenced requirements such as high ride quality. So, the active suspension should be designed to supplied the optimized suspensnion condition actively and to perform the optimal ride quality on the irregula running condition such as on the enterance or exitance of the tunnel or on the crossing the high speed train each others. On this study, the train dynamic model, integration of active suspension system, and the control logic would be proposed, and the advanced performace of train would be shown though the simulation tests.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.88-97
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• 1998

Compliance elements such as bushings of a suspension system play a crucial role in determining the ride and handling characteristics of the vehicle. In this paper, a general procedure is proposed for the optimum design of compliance elements to meet various design targets. Based on the assumption that the displacements of elastokinematic behavior of a suspension system under external forces are very small, linearized elastokinematic equations in terms of infinitesimal displacements and joint reaction forces are derived. Directly differentiating the linear elastokinematic equations with respect to design variables associated with bushing stiffness, sensitivity equations are obtained. The design process for determining the bushing stiffness using sensitivity analysis and optimization technique is demonstrated.