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This paper presents the development of a hardware in the loop (HIL) simulation system for evaluating and optimizing the interactions of the brake system with the vehicle. This unique HIL set-up consists of an inertial brake dynamometer with a brake corner module, an electronic control unit, a real time 3D total vehicle model and a computer system with a high-speed operating platform. The HIL system simultaneously confers advantages of both computer modeling and hardware testing. It offers the capability to do upfront design and assess performance of the foundation brake hardware and the chassis controls, as well as their interactions, in advance of testing and tuning a vehicle. This powerful tool enables reduction in development time and cost. A simple example of applying the brake dynamometer HIL system will be presented.

Friction behavior is one of the most critical factors in brake system design and performance. For up-front design and system modeling it is desirable to be able to describe a lining's frictional behavior as a function of the local conditions, such as contact pressure, temperature and sliding speed. Typically, frictional performance is assessed using brake dynamometer testing of full-scale hardware, and an average friction value is used during brake system development. This traditional approach yields an average brake friction coefficient that is hardware-dependent and fails to capture in-stop friction variation; it is also unavailable in advance of component testing, ruling out true up-front design and prediction. To address these shortcomings, a scaled inertial brake dynamometer was used to determine the frictional characteristics of candidate lining materials.

A general methodology is presented which can be used to generate computer based models for simulating the transient response of vehicle systems. The vehicle rail shipping impact analysis has been conducted by using the presented methodology. A system topology of the vehicle model is represented by the graphical representation. The system model is composed of rigid bodies, nonlinear bushing joints and may closed kinematic loops. The formulation and solution of vehicle system equations is often difficult and expensive because of the large number of algebraic constraints and dependent variables. The modeling and simulation procedures reveals that substantial algorithm simplicity and computational efficiency can be achieved by taking advantage of system topology, matrix methods and other numerical techniques to effectively eliminate excess equations and variables.