Parameter-Controlled Automotive ABS Simulation

In this study, we developed simulation modules using Matlab/Simulink's block-based modeling environment, implementing vehicle dynamics equations through custom S-functions and predefined library blocks. The simulation experiments generated data for vehicle speed, wheel slip ratio, and braking distance curves, with the results compared against non-ABS braking scenarios showing satisfactory performance. This establishes a foundation for building comprehensive vehicle dynamics simulation platforms, where the modular structure allows for easy integration of additional subsystems.

Using Matlab/Simulink's parameter sweep functionality and control system toolbox, we analyzed model behavior under both high and low friction coefficient road conditions. The study investigated ABS parameter impacts through systematic variation of control parameters in the PID controller blocks, revealing key relationships between system variables. Our findings include:

1) Higher brake pressure variation frequency, implemented through pulse-width modulation in the control algorithm, significantly reduces wheel lock-up tendency. When modifying braking force frequency using Simulink's signal generator blocks, braking distance shows negligible changes due to the ABS controller's adaptive threshold logic.

2) Within normal ABS operational range, variations in brake pressure gain (controlled through amplifier blocks in the simulation) demonstrate minimal impact on braking effectiveness. Increasing braking force gain through parameter tuning doesn't effectively reduce stopping distance, as confirmed by multiple simulation runs with different gain settings.

3) On low-friction surfaces (like loose snow and icy roads), the ground adhesion coefficient remains relatively constant within slip ratios of approximately 0.1 to 1.0. The ABS system, modeled with hysteresis control logic, cannot respond as rapidly as on high-friction surfaces. However, despite longer baseline braking distances, the ABS system still contributes significantly to distance reduction while maintaining directional stability through the wheel speed difference monitoring algorithm.