Braking Distance Estimation with Dynamic Brake Friction Modeling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for determining braking distance assume a constant coefficient of friction between brake pads and discs, leading to inaccuracies due to temperature variations and changing friction conditions during braking, which significantly deviate from real-world scenarios.
Innovation Solution
A method that calculates braking distance by accounting for current vehicle speed, clamping force, and surface temperature-dependent friction coefficient, incorporating thermal and vehicle dynamics functions to iteratively update friction coefficient and temperature throughout the braking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant coefficient of friction is assumed throughout the braking determination, then the calculation method is simple, but the braking distance estimation accuracy deteriorates significantly
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static constant friction coefficient model to a dynamic time-varying friction coefficient model. The friction coefficient is updated at each time step based on current temperature conditions, allowing the system to adapt to changing thermal states during braking. This resolves the contradiction by introducing temporal variability that improves accuracy while maintaining computational feasibility through iterative calculation.
Solution Approach 2:
The patent implements parameter changes by making the friction coefficient a function of temperature rather than a constant value. The temperature-dependent friction coefficient model allows the parameter to change dynamically based on thermal conditions. This approach improves braking distance estimation accuracy by accounting for the physical reality that friction characteristics vary with temperature, while the mathematical formulation remains tractable for computational implementation.
2Measurement precision
If temperature-dependent friction coefficient is considered, then the braking distance accuracy is improved, but the calculation complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the braking process into discrete time steps. At each time step, the friction coefficient is calculated based on the current temperature, and the process is iterated for the next time step. This temporal segmentation transforms a complex continuous problem into a series of simpler discrete calculations, improving accuracy by capturing temperature variations while managing computational complexity through stepwise processing.
Solution Approach 2:
The patent implements feedback by using the calculated temperature at each time step to determine the friction coefficient for that same time step, which then influences the braking force calculation, which in turn affects the temperature evolution in the next time step. This closed-loop feedback mechanism allows the system to automatically adapt to changing conditions, improving accuracy while the iterative nature provides a systematic approach to managing the increased calculation complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a more accurate estimation of braking distance by dynamically considering the changing friction conditions, resulting in a braking distance calculation that better reflects real-world scenarios, with improved assessment of braking performance.
Implementation Method 1
the temperature of the friction layer increases when the train is subjected to greater load... the temperature of the friction layer (the disc surface or the wheel tread) varies depending on different braking situations
Implementation Method 2
the coefficient of friction (COF) is highly temperature-dependent... the friction coefficient, in turn, depends on the temperature of the friction layer
Data Source
Figure 1
Figure 2
AI summary
A method for determining a braking distance of a vehicle, wherein a coefficient of friction COFactual between a brake lining and a brake disc is calculated as a function of a tensioning force Fd, a vehicle velocity V and a temperature of the frictional layer Tdisc, wherein the temperature of the frictional layer Tdisc is updated dynamically on the basis of the coefficient of friction COFactual in order to calculate a braking distance which approaches reality.