Mathematical modelling and an experimental study for vehicle braking force analysis

Taşıtlarda frenleme performansı, fren sisteminin durumunu ortaya koyması bakımından oldukça önemlidir. Frenleme performansını, fren sistem elemanları ve tekerlek-yol şartları gibi faktörler doğrudan etkilemektedir. Bu faktörlerin fren kuvvetleri üzerindeki etkileri, deneysel yöntemlerle tespit edilebileceği gibi matematiksel modeller yoluyla kestirilmesi mümkündür. Bu çalışmada; fren kuvvet analizi deneysel ve matematiksel model ile yapılmıştır. Bu amaçla hidrolik fren test cihazı elektronik hale dönüştürülmüştür. Geliştirilen model ile değişik tekerlek-yol şartlarmdaki fren kuvvetlerinin doğru bir şekilde hesaplanması sağlanmaktadır. Bu model ile frenleme kuvvetini doğrudan etkileyen, lastik tırnak derinliği, zemin şartlarının değişimi, lastik hava basıncı, vb etkenlerin formüle edilmesi sağlanmıştır. Frenleme kuvvetinin kayma oranına göre değişimi; bir parametre değişirken diğer parametreler sabit alınarak hesaplanmış ve 3 kN düşey yük için yapılmıştır. Matematiksel modelde $R^2$ değeri 0.967 ile 1.0 arasında değişmektedir.

Taşıtlarda frenleme kuvveti analizi için matematik modelleme ve deneysel bir çalışma

Braking performance is an important criteria for the vehicle safety and for the conditions of brake system elements. Many factors such as the wheel-road interaction and elements of brake system condition affect the brake performance. However these factors can be measured by brake test equipment, brake forces for a vehicle can also be analyzed by using mathematical models. In this experimental study, brake force analysis has been done by measuring the changes of brake forces and by using a mathematical model based on the obtained experimental data. For this purpose, hydraulic brake test equipment has been developed by using electronic equipment and a data acquisition system. By using the developed equipment, a mathematical formulation is obtained by considering the effective factors of brake force i.e, the tire thread depth, the variation of road conditions, tire air pressure etc. There is a good agreement between the experimental data and the developed mathematical model. The change of braking force with respect to the ratio of sliding was calculated; when one parameter was changing, the others was kept constant in this calculation and this was done using 3 kN vertical force. The statistical coefficient of multiple determinations (R2 value) varied between 0.967 and 1.0.

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