A Control Algorithm Of Braking Force Distribution For The Electronic Braking System Of Bus

Brake system is the most important part on bus for safety, and its performance isdirectly related to the safety of passengers and their property. The disadvantages ofconventional air brake system, such as response delay and unreasonable braking forcedistribution, may cause serious accidents. Therefore, manufacturers developed theElectronic Braking System (EBS) on the basis of ABS. By braking electronically,vehicle performance can be improved as a result of the significantly reduced responsetime, which is very important to avoid accidents.This work was financially supported by the National Natural Science FoundationProject of "Research on multi-objective control for heavy-duty trailer stability basedon model "(No.:51075176). This thesis focused on a control algorithm of brakingforce distribution for the electronic braking system of bus in uncritical brakingconditions, a15-DOF vehicle model and a hardware in the loop simulation benchwere built respectively, and the control algorithm was verified by softwaresimulations and experiments performed on the hardware in the loop simulationbench. The main work is summarized as follows:(1)A15-DOF vehicle model of bus was built in a modular modeling approach.By masking properly, the operation speed was improved to meet the requirements ofsoftware co-simulations and HILS bench for accuracy and real time datacommunication. Simulations were performed on high and low adhesion roads indifferent load conditions. The accuracy of the model was verified by comparingsimulation results of the model with those of TruckSim.(2) A load estimation method based on engine torque, acceleration of the vehicleand load sensor was proposed, which enabled the reasonable distribution of brakingforce between the front and rear axles based on dynamic axle loads. Thecorrespondence between the brake pedal and the objective brake rate was determined based on vehicle test.(3)A control algorithm of braking force distribution based on dynamic axle loadwas proposed so that the adhesion utilization of each axle was equal to the brakingrate of the vehicle. The braking force at each wheel was adjusted according to thedifference between the vehicle’s actual braking rate and the objective braking rate tomake the acceleration independent from load conditions. A brake pad wear controlalgorithm was proposed to reduce the difference in brake pad wear between the frontand rear axles. Simulations were performed to verify the algorithm.(4) A hardware-in-the-loop simulation test bench was built, tests on some keycomponents of EBS such as the brake value sensor, proportional relay valve and axlemodulator were conducted and their characteristics were obtained. HILS experimentswere carried out and the results showed that the control algorithms could workproperly in different braking conditions.