• 한국자동차공학회논문집
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• 제6권5호
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• pp.128-137
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• 1998

A numerical approach for performing kinematic design sensitivity analysis of vehicle suspension systems is presented. Compared with the conventional analytical methods, which require explicit derivation of sensitivity equations, the proposed numerical method can be applied to any type of suspension systems without obtaining sensitivity equations, once any kinematic analysis procedure is established. To obtain sensitivity equations, a numerical differentiation algorithm that uses the third order Lagrange polynomial is developed. The algorithm efficiently and accurately computes the sensitivity of various vehicle static design factors with respect to kinematic design variables. Through a suspension design problem, the validity and usefulness of the method is demonstrated.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.198-203
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• 2003

Due to the low production cost and space availability which are originated from the structural simplicity of the torsion beam axle suspension, the suspension has been frequently used for sedan and SUV style vehicles. The design procedure of the suspension, however, requires significant amount of time which prohibits more efficient design of the suspension. In this study, an integrated procedure and constituting modules are explained and the performance of the corresponding program is exhibited. The integrated procedure enables one to save the design time and cost significantly.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.121-127
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• 2003

The stiffness of a bushing in a suspension is extremely important for the overall performance of the suspension system. A new measurement system including the flexible jig was developed to measure the multi-directional stiffness of bushings. To overcome the disadvantage of building each individual jig for each type and size of a bushing, we designed the flexible jig which can accommodate numerous bushings of similar shapes and sizes. Upon using the novel design of the flexible jig in the industry, we could successfully measure the torsional and conical stiffness of many bushings and apply the data for the prediction and evaluation of the performance of a suspension system, which would assist designing the optimal suspension system.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.27-37
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• 1996

In this paper the effects of suspension design parameters on the steady-state cornering performance of vehicles are studied. To investigate the understeer characteristics of vehicles, steady-state cornering equatons are derived from a two-track model which is expanded from a simple one track model. The effects of the suspension design parameters as well as those of lateral load transfer are taken into consideration. To verify the equation, a skid pad test was carried out with a domestic passenger car. The design parameters of the vehicle are measured using a Suspension Parameter Measuring Device(SPMD). Based on these results, parameter studies are carried out to determine the effect of design parameters on the cornering performance of a vehicle, both in low and high acceleration region.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.109-118
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of field test results and simulation results of the ADAMS/Car demonstrates the validity of the proposed functional suspension modeling method. This model is suitable for real-time vehicle dynamics analysis.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.99-108
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• 2005

This paper represents an efficient modeling method of a suspension system for the vehicle dynamic simulation. The suspension links are modeled as composite joints. The motion of wheel is defined as relative one degree of freedom motion with respect to car body. The unique relative kinematic constraint formulation between the car body and wheel enables to derive equations of motion in terms of wheel vertical motion. Thus, vehicle model has ten degrees of freedom. By using velocity transformation method, the equations of motion of the vehicle is systematically derived without kinematic constraints. Various vehicle simulation such as J-turn, slowly increasing steer, sinusoidal sweep steer and bump run has been performed to verify the validity of the suggested vehicle model.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.150-158
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• 2002

Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.216-223
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• 1999

This study was intended to determine the inertia , damping and stiffness properties of the cab-suspension of agricultural tractors by applying the direct system identification method (DSIM). Since the rigid and elastic modes of the cab-suspension are not likely to be separated clearly, direct application of the DSIM may result in large computation error. To solve such a problem, a method of locating mass center of the cab were determined by assuming the behavior of the cab-suspension is a rigid body motion. The dynamic parameters of the cab-suspension were then determined by applying the DSIM with the known coordinates of the mass center. The constraints of spatial matrices of the cab-suspension also make the algorithm for the DSIM perform better. The values of dynamic parameters determined by this method agreed well with those determined by the experiment.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.25-30
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• 2006

This study is about an optimum design to improve the kinematic and compliance characteristics of a torsion-beam suspension system. The kinematic and compliance characteristics of an initial design of the suspension was obtained through a roll-mode analysis. The objective function was set to minimize within design constraints. The coordinates of the connecting point between the torsion-beam and the trailing arm were treated as design parameters. Since the torsion-beam suspension has large nonlinear effects due to kinematic and elastic motion, Genetic Algorithms were employed for the optimal design. The optimized results were verified through a double-lane change simulation using the full vehicle model.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.138-147
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• 2000

Vehicle suspension systems are parts which effect performances of a vehicle such as ride quality, handing characteristics, straight performance and steering effort etc. Kinematic design is a decision of joints` position for straight performance and steering effort. But, when vehicle is rebounding and bumping, chang of joints` displacement is nonlinear and a surmise of straight performance and steering effort at that joints` position is difficult. So design of suspension systems is done through a inefficient method of tried-and-error depending on designer`s experience. In this paper, kinematic design of suspension systems was done through the optimal design using a genetic algorithm. For this optimal design, the function for quantification of straight performance and steering effort was made, and the kinematic design method of suspension systems having this function as the objective function was suggested.