• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1287-1296
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• 2003

In this paper the dynamic analysis of the Macpherson strut motor-vehicle suspension system is presented. The equations of motion are formulated using a two-step transformation. Initially, the equations of motion are derived for a dynamically equivalent constrained system of particles that replaces the rigid bodies by applying Newton's second law The equations of motion are then transformed to a reduced set in terms of the relative joint variables. Use of both Cartesian and joint variables produces an efficient set of equations without loss of generality For open chains, this process automatically eliminates all of the non-working constraint forces and leads to an efficient solution and integration of the equations of motion. For closed loops, suitable joints should be cut and few cut-joints constraint equations should be included for each closed chain. The chosen suspension includes open and closed loops with quarter-car model. The results of the simulation indicate the simplicity and generality of the dynamic formulation.

• 한국정밀공학회지
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• 제17권1호
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• pp.34-44
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• 2000

In this paper, a modified skyhook control for the semi-active Macpherson suspension system is investigated. A new model for the semi-active type suspension, which incorporates the rotational motion of the unsprung mass, is introduced and an output feedback control law using the skyhook control method is derived. The gains in the skyhook controller are adaptively adjusted by estimating the road conditions. Because two vertical acceleration sensors, one for the sprung mass and another for the unsprung mass, are used rather than using the angle sensor for the rotational motion of the control arm, the relative velocity of the rattle space is filtered using the acceleration signals. For testing the control performance, the actual damping force has been incorporated via the hardware-in-the-loop simulations. The performances of a passive damper and a semi-active damper are compared. Simulation results are provided.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.157-164
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• 2016

이 논문은 MR 댐퍼를 적용한 맥퍼슨 타입의 반 능동 현가장치의 진동제어에 관한 연구를 보여준다. 맥퍼슨 스트럿의 기하학적 분석을 바탕으로 동역학 지배 방정식이 설립되었으며, 제어기 설계를 위해 평형 점 근처의 비선형적 운동이 선형화하였다. 이어서 시스템의 향상된 반응시간을 위해 새로운 적응 움직임 슬라이딩모드 제어기를 제안하였으며, 시뮬레이션을 통해 범프와 랜덤도로에서 차량으로 가해지는 진동에 따른 제어 성능을 기존슬라이딩모드 제어기 및 스카이훅 제어기와의 비교를 통해 우수성을 평가하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제8권1호
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• pp.67-80
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• 2004

In the present paper, a numerical algorithm for the kinematic analysis of a MacPherson strut motor-vehicle suspension system is developed. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. The presented formulation in terms of this system of coordinates is simple and involves only elementary mathematics. The resulting constraint equations are mostly either linear or quadratic in the rectangular Cartesian coordinates. The proposed formulation eliminates the need to write redundant constraints and allows to solve a reduced system of equations which leads to better accuracy and a reduction in computing time. The algorithm is applied to solve the initial positions as well as the finite displacement, velocity and acceleration problems for the MacPherson strut motor-vehicle suspension system.

• 제어로봇시스템학회논문지
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• 제9권9호
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• pp.669-678
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• 2003

A road-adaptive LQG control for the semi-active Macpherson strut suspension system of hydraulic type is investigated. A new control-oriented model, which incorporates the rotational motion of the unsprung mass, is used for control system design. First, based on the extended least squares estimation algorithm, a LQG controller adapting to the estimated road characteristics is designed. With computer simulations, the performance of the proposed LQC-controlled semi-active suspension is compared with that of a non-adaptive one. The results show better control performance of the proposed system over the compared one.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.47.5-47
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• 2001

In this paper. a road-adaptive LQG control for the semiactive Macpherson strut suspension system of hydraulic type is investigated. A new control oriented model, which incorporates the rotational motion of the unsprung mass, is introduced. A semi-active suspension controller adapting to road variations is proposed. First, based on the extended least squares estimation algorithm, a LQG controller adapting to the estimated road characteristics is designed. Through the computer simulations, the performance of the proposed semi-active suspension is compared with that of a non-adaptive one. The results show better control performance of the proposed system over the compared one.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.194-202
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• 2014

Steering axis of suspensions is an important factor that affects ride and handling quality in the vehicle chassis development. Macpherson strut and double wishbone's steering axis are defined geometrically, but multi-link suspensions can not be geometrically analyzed. In this case instant axis theory is commonly used to find a steering axis. Since the steering axis is moving with varying caster and kingpin inclination angle, this method approximately corresponds with exact solution. In this paper, we propose a velocity analysis method to find a pure rotational axis of the wheel relative to suspension arms, that is exact solution of the steering axis. This paper extends the method to analyze the steering axis of multi-link suspensions with bushing compliance. The analysis results applied to double wishbone and multi-link suspensions demonstrate validity and accuracy of the proposed method.

• 한국자동차공학회논문집
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• 제13권6호
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• pp.142-153
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• 2005

The brake judder is a phenomenon that the steering wheel is abnormally vibrating when the car is braked at a high speed. It is classified by the cold and the hot judder. The former is generated due to the initial uneven disk surface and the latter is resulted from the uneven heat spots on disc surface by repeatedly braking. There are two ways to reduce the judder. One is to control vibration by modification of the disk shapes and pad ingredients. The other is to improve modal characteristics of the suspension system. The latter approach is used in this research. In this paper, the real vehicle test and computer simulation are considered to systematically understand the judder phenomenon of the vehicle. The Macpherson strut suspension is employed. Especially, the judder sensitivity is calculated based on design sensitivity analysis. A bush stiffness was reworked and braking test was done to verify the sensitivity result. The judder reduction by the mode control was verified.