The prevention and control of brake judder and its various negative effects has been a key target of vehicle production. One of the effects is the steering wheel vibration during vehicle braking. Experimental and theoretical investigation into “steering wheel vibration due to brake judder” is extensively presented in this paper.
The vehicle road test is carried out under controlled braking conditions. During the test, the accelerations of brake caliper assembly, suspension low and upper control arm, steering arm, tie rod and steering wheel, left and right wheel rotary speed, are measured by a multi-channel data acquisition system. The data processing focuses on order tracking analysis and transfer path analysis to work out the related resonant components. A disc brake assembly, with deliberately designed disc thickness variation and surface run-out combinations, is tested on a brake dynamometer. And the signals of disc deformation, disc surface temperature, caliper acceleration, hydraulic pressure, speed and braking torque are simultaneously measured. Based on the data analysis, the friction-thermal-mechanical coupled effect of disc brake, the contribution of DTV and SRO to torque and pressure fluctuations are described.
At the same time, modeling and simulation are carried out to reproduce and explain the vehicle road test and brake dynamometer test. A friction-thermal-mechanical coupled dynamics simulation of disc brake is programmed in MATLAB. And a multi-body-dynamic vehicle model with a full description of tire road friction, suspension and steering system, rubber bushings and vehicle inertia, is also established in ADAMS. On the basis of the comparison between the numerical results and the measurement results, the two models are validated and optimized. In sum, the two models are proved effective in predicting and validating of the influences of various factors from disc brake system, suspension system, steering system and tire, and therefore, they can be used for chassis design to control steering wheel vibration due to brake judder.