Simulation of an active disc brake with hydro-mechanical torque control

Hydraulic disc brakes are used in trains and light rail vehicles because of their high power density, compact design, and good dynamic performance. Their braking torque is seldom part of a closed-loop control and no counteracting action is usually taken against the disturbances acting in the contact zone between brake pads and disc, where a variable friction coefficient arises. Consequently, phenomena such as brake fade and judder may occur, leading to passengers’ uneasiness and degradation of the braking performance. In this work, an actual active brake disc of floating caliper type will be analyzed, modelled and simulated on the multidomain platform LMS AmeSim and the effect of an inconsistent friction coefficient on its braking torque will be highlighted. A closed loop concept will be introduced and a hydro-mechanical control unit will be deployed to enhance the system behavior in presence of disturbances and to ensure accuracy and repeatability in the generated braking torque.