Effect of load transfer of tractor-semitrailer on cornering braking stability

A cornering braking dynamics model of tractor-semitrailer was established. Its accuracy was verified by comparing its outputs with the test data of tractor-semitrailer. By the model simulation of cornering braking process, the changes of vertical loads on coaxial left and right wheels were analyzed, and their effects on wheel locking order and braking stability were carried out. The effect of brake chamber's pressure increase on cornering braking stability was studied. Simulation result indicates that when the maximum braking pressure is 0.62 MPa, the right wheel vertical load of tractor steering shaft increases from 12.00 kN to 23.00 kN, but the left wheel vertical load decreases from 12.00 kN to 0.66 kN, so load transfer is significant. When the maximum braking pressure increases, the load transfer obeys the same regulation, which affects the locking trends of coaxial left and right wheels and the work time of ABS. When the maximum braking pressure increases from 0.62 MPa to 1.50 MPa, the folding angle of tractor-semitrailer decreases from 0.73 rad to 0.67 rad, so the cornering braking stability improves.