• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.465-472
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• 2008

An automotive windshield wiper system is modeled mainly for vibration analysis purpose. The model is composed of solid links, ideal joints, imperfect joints to simulate unavoidable manufacturing defects and bushings having stiffness, contact between a wiper blade and a wind screen glass, friction, a spring and an actuator. Main stream of wiper dynamics analysis has been obtaining a closed form of system of equations using Newton's or Lagrange's formula and doing a numerical simulation study to understand and predict the behavior of it. However, the modeling process is complex since a wiper system is of multibody and a contact problem occurs. When imperfection, such as dead zone of a joint and stiffness of a rubber bushing, should be included, the added complexity makes the modeling difficult. Since the imperfection is understood as main cause of problematic vibration, the dynamics model of a wiper system aiming vibration analysis should include such unavoidable manufacturing defects in the model. An open form of dynamic model of a automotive windshield wiper system with imperfect joints using a commercial software is obtained and a simulation analyssis is conducted for vibration reduction study.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.51-57
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• 2006

The contact pressure distribution between a rubber wiper blade and a glass windshield is a major factor for wiping performance. A modeling and simulation method has been developed to forecast the contact pressure distribution on a wiper blade. For modeling multi-body dynamics of an wiper linkage system and flexible nature of wiper blade, ADAMS and ADAMS/flex are employed. A simulation study has been also conducted to obtain contact pressure distribution. Comparison between simulation and measurement is provided to ensure fidelity of the model and the simulation method.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.79-83
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• 2010

Recently, the flat wiper which is one piece wiper and subjected to a pressing force at a single center point is gaining wide applications on automotive windshields. However, nonuniform reactive pressure distributions takes place, so that wiping is not completed at such locations. The wiping performance of the flat wiper is best when a wiper and a curved windshield have perfect contact without gaps under the specified pressing force of 13 ~ 15 gf/cm. Therefore, it is necessary that the realistic curvature equation of a wiper spring-rail should be obtained. Finite element analysis, CATIA script-macro function, and the least square method were utilized to find out the curvature of a spring-rail for a perfect contact with a windshield under a specified concentrated load. The curvature equation became the third order polynomial.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1727-1730
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• 2003

A windshield wiper system plays a key part in assurance of driver's safety at rainfall. However, because quantity of rain and snow vary irregularly according to time and velocity of automotive, a driver changes speed and operation period of a wiper from time to time in order to secure enough visual field in the traditional windshield wiper system. Because a manual operation of windshield wiper distracts driver's sensitivity and causes inadvertent driving, this is becoming direct cause of traffic accident. Therefore, this paper presents the basic architecture of vision-based smart windshield wiper system and the rain sensing algorithm that regulate speed and operation period of windshield wiper automatically according to quantity of rain or snow. Also, this paper introduces the fuzzy wiper control algorithm based on human's expertise, and evaluates performance of suggested algorithm in simulator model. In especial, the vision sensor can measure wide area relatively than the optical rain sensor. hence, this grasp rainfall state more exactly in case disturbance occurs.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.134-140
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• 2003

The film sensor is used for measuring pressure distribution at planar area, especially at a small space or gap. The present paper deals with the development of film type sensors and system for pressure distribution measuring. The developed system is consist of (1)film sensor with 40/sup */40 array, (2)PCI interface card with maximum sampling rate of 100㎐, and (3)software for data processing and real-time display. The contact pressure test of wiper blade and front glass of vehicle was performed with wiper blade by 40cm. Generally spring force of wiper arm is designed at 0.7∼1kN. Test results of total force was 9.4N and 7.1N in each driver and passenger toward. The paper suggested possibility for base definition in wiper design. A windshield wiper blade experiment revealed that the system successfully measured the contact force distribution during static state, showing the usefulness of the developed system.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.83-90
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• 2010

The windshield wiper consists of 4 parts: a blade, an arm, a linkage and a motor. The wiper blade makes contact with the windshield and is designed to be operated normally at an angle of 30~50 degrees to the front glass. If the contact pressure between the wiper blade and windshield surface is too high, noise and wear of the rubber will result. On the other hand, if the contact pressure is too low, the performance will do badly, since foreign substances such as dust and stains will not be removed well. The pressure and friction of the wiper blade has a great influence on its effectiveness in cleaning the front window. This is due to the contact of the rubber with the window. This paper presents the dynamic analysis method to estimate the performance of the flat type blade of the wiper system. The blade has a nonlinear characteristic since the rubber is an incompressible hyper-elastic and visco-elastic material. Thus, Structural dynamic analysis using a complex contact model for the blade is performed to find the characteristics of the blade. The flexible multi-body dynamic model is verified by the comparison between test and analysis result. Also, the optimization using the central composite design table is performed.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.292-298
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• 2015

A wiper is a safety device removing rain and debris from windshield and ensuring visibility of drivers. If contact pressure distribution between rubber of the blade and the windshield is unbalanced, unwanted noise, vibration, and abrasion of the blade can occur and sometimes fatal accidents could occur. To improve the safety of the wiper, there have been many researches on the contact pressure analysis of the wiper, but the analysis results were not converged or require much computational time due to material nonlinearity of the rubber and contact conditions between the blade rubber and the windshield. In this research, a simple model with 1D beam and 2D shell elements was used for the contact pressure analysis instead of the 3D blade model. The simplified model saved computational time of the analysis and resolved convergence problems. The accuracy of the analysis results was verified by comparing them with experimental results for different rail spring curvatures.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.58-65
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• 2005

A method measuring angular speed and estimating angular acceleration of an automotive wind shield wiper pivot with limited resources has been proposed. Limited resources refer to the fact that processes cannot be operated in real-time with a regular notebook running a Microsoft Windows. Also, they refer to the fact that data acquisition cards have only two general purpose counters as many generic cards do. An optical incremental encoder has been employed for measuring angular motion. To measure the angular speed of the pivot, periods for the encoder's output pulses have been measured as the speed is related to the reciprocal of the period. Since only information acquired from one counter channel is the magnitude of the angular speed, sign correction is necessary. Also the information for the exact time when a pivot passes left and right dead points is also missing and the situation is inherent to the hardware setup. To find out the zero-crossing time of the angular speed, a linear interpolation technique has been employed. Lastly, to overcome the imperfection of the mechanical encoders, the angular speed has been curve fitted to a spline. Angular acceleration can be obtained by a differentiation of the angular speed.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.649-657
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• 2004

A windshield wiper system plays a key part in assurance of driver's safety at rainfall. However, because quantity of rain and snow vary irregularly according to time and velocity of automotive, a driver changes speed and operation period of a wiper from time to time in order to secure enough visual field in the traditional windshield wiper system. Because a manual operation of wiper distracts driver's sensitivity and causes inadvertent driving, this is becoming direct cause of traffic accident. Therefore, this paper presents the basic architecture of vision-based smart wiper system and the rain sensing algorithm that regulate speed and interval of wiper automatically according to quantity of rain or snow. Also, this paper introduces the fuzzy wiper control algorithm based on human's expertise, and evaluates performance of suggested algorithm in the simulator model. Especially the vision sensor can measure wider area relatively than the optical rain sensor, hence, this grasps rainfall state more exactly in case disturbance occurs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.837-842
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• 2010

The wiper system of a vehicle is important because it wipes the windshield, thereby enabling drivers to see through the windshield even under conditions of rain and snow. The blade is the key component of the wiper system because it wipes the windshield. When wiper-arm spring causes the blade to be pressed on the windshield optimum performance of wiping can be achieved when appropriate contact pressure is maintained. In this study, a dynamic analysis of the wiper system is carried out. A three-dimensional finite-element model of the wiper system is generated using SAMCEF, a commercial structural dynamic analysis program. The distribution of the contact pressure of the blade in its dynamic state is calculated. The simulation result is compared to the experiment result. Using the results of this study, the contact pressure of the blade can be estimated.