Objective characterization of brake systems in motorcycles

This research presents an objective approach to the brake characteristics of state-of-the-art hydraulic motorcycle brake systems. Research in literature reveals a lack of objective characterization criteria for motorcycles. The relevant characteristic parameters from studies on car brake systems are used to develop a measuring unit meeting the demands for a mobile, reproducible and precise testing system. The concept and validation of this device is presented. This measuring device has been used to measure different motorcycles representing different concepts, and their brake characteristics are shown. The effects on the brake stiffness of typical brake uncertainties, such as air intrusion, are measured and presented. As the automobile brake system is a typical human machine interface used to control deceleration, both technical system parameters and psychophysical aspects are considered in order to objectify the brake characteristic. As a result, this research provides a novel definition of the colloquial pressure point, using measurable parameters such as the pedal characteristic defined by force as a function of displacement. Through an analytical approach two characteristic points, representing the force feedback at the lever and the deceleration feedback of the vehicle are defined. The difference between these points is an objective measure for controllability of the brake system.