An Electric Parking Brake Motor-On-Caliper actuator model for robust drive away control design

摘要

Electric Parking Brake system is the automation of traditional manual vehicle parking brake system. Naturally, an automation in automotive field includes an improvement of vehicle features that will become, in short time, normal production functionalities, since forever present on vehicles for users. Certainly, EPB control design is a robust design which is influenced by a series of different plant disturbances / uncertainties as: available vehicle battery voltage, ambient/caliper/pad temperatures, vehicle harness length, and normal braking hydraulic pressure already present on caliper spindle. Furthermore EPB system performance has a big impact on vehicle safety, ECE 13H braking legislation part related to parking brakes prescribes many different performance thresholds, static and dynamic, that are easily translated in low level control design requirements. In this context, paper presents: an algebraic mathematical model, including linear and non-linear parts of braking motor-on-caliper, dynamic response identification of electric parking brake actuator by least square identification experiments, linearization of identified non-linear model, observability analysis of identified linear model, and control of Motor on Caliper (MoC) validated with MIL and HIL approach. The simulation and experimental results on a motor-on-caliper test bench, carried out in FCA Technical Center, show that designed identified model is well matched with the clamping force actuator, and it can be useful in drive away robust control logics development.