Research On Cornering Braking Stability And Control Of A Heavy Vehicle Based On Co-Simulation

When vehicle drives on road curved section, applied brake is a very dangerousconditions in this process, most of the vehicles in the non-linear region, the lateralforce provided by tire can not be balance the external lateral forces, resulting in lossof stability, the occurrence of drift, sliding, out of orbit and so on. Currently on heavyvehicle steering control study less and control methods are simple, and all theresearch did not involve nonlinear dynamics.Therefore, in this paper，contrary toheavy vehicle steering system nonlinear factors and cornering brake stability werestudied. Specific work is as follows:First of all, A closed-loop Driver-Vehicle-Road model with two degree offreedom (DOF) for a three-axe heavy vehicle was set up. Considering the influence ofthe road directional disturbance and driver control, the vehicle ordinary differentialequations of motion were established. The influences of system parameters includingwheelbase, preview distance, loading, time delay of driver control, tire lateralstiffness on steering stability were studied by numerical simulations, based on theHopf bifurcation theory. The range of numerical stability of the steering system wasalso determined. Moreover, the nonlinear dynamics of this closed-loopDriver-Vehicle-Road system on different vehicle running speed were investigated bynumerical methods, such as bifurcation, time history curve, phase trajectory, powerspectrum, poincare section and Lyapunov exponent.Then, based on multi-body dynamic method and virtual prototyping technology,a nonlinear heavy vehicle dynamic model was built in ADAMS/CAR, including thefront and rear suspension system, vehicle body, engine system, steering system,antiroll system, brake system, and tire dynamic model. The nonlinear characteristicsof the tire, bushing, spring and damper are considered so as to express the dynamicsperformance of the vehicle accurately.Finally，A fuzzy controller system was designed for improving heavy vehicleyaw stability in this paper. The control objective of this system were yaw rate and body sideslip angle, by differential braking, a corrective yaw moment is generated toensure the vehicle yaw stability significantly improving，moreover，the controller usestwo brake force distribution strategy, namely dual-channel control and six-channelcontrol.The control system was combined with the vehicle dynamic mode1by dataexchange interfaces between two kinds of software. Analysis of the affluence underthe different speeds, braking acceleration, load, road adhesion coefficient (Dry asphalt,wet concrete, ice and snow) and bend radius. The result shows the yaw controllersystem with the differential braking fuzzy control can reduce the Yaw rate, sideslipangle and lateral acceleration apparently. And then improve the heavy vehicle yawstability.