To improve driving stability of bus driver in high-speed turning and obstacle avoidance in high speed driving condition, a vehicle model and an electronic control pneumatic system model is firstly established. Then, based on the super twisting algorithm, an additional yaw moment controller is designed for bus anti-rollover. The disturbance term of the system is estimated through a nonlinear disturbance observer, and it is compensated to the controller. Finally, the co-simulation of MATLAB/Simulink, TruckSim and AMESim is carried out. The simulation results show that compared with PID control, the algorithm proposed in this article can reduce the roll angle by 0.2° and 0.7° respectively under steering wheel step conditions and fishinghook conditions.

The micro-speed difference dual-rotor system composed of a hydraulic torque converter and a crankshaft affects the idle twitch of an Automatic Transmission (AT) vehicle. Through the Hilbert transform of the dynamic unbalanced coupling excitation force of the dual-rotor system, it is revealed that the beat vibration of the component is the root cause of the regular idle twitch. The maximum twitch amplitude is the sum of the excitation forces, and the twitch time interval is the difference between the excitation force frequencies. The Automatic Dynamic Analysis of Mechanical Systems (ADAMS) model including engine, transmission and mounting system is established and simulated. The results show that the closer the vertical rigid body mode of the powertrain is to the excitation frequency, the greater the vertical first-order dynamic stiffness of the hydraulic mount and the greater the vibration amplitude. Therefore, the idle twitch can be improved by the frequency avoidance design of the Z-direction mode of the powertrain and the dynamic unbalance excitation frequency of the crankshaft, reducing the vertical dynamic stiffness of the hydraulic mount, and improving the vibration isolation performance of the mount system.

In order to analyze the performance of the shifting system and design the parameters of the shifting system parts, the transmission model of shift execution system has been established, and combined with Trapezoidal Back-EMF and square wave control principle of Brushless Direct Current (BLDC) motor, Simulink control model of motor module is established. ADAMS is used to import physical parameteric model, the interactive simulation of motor model and mechanical system is realized through ADAMS interface. Drum fixed torque loading simulation and motor three-ring control principle are applied to analyze system response characteristic and process parameters of the dynamic shifting process. Simulation and test results show that motor torque loading process impacts remarkably system function realization, parts shifting forces and shifting duration. Selecting appropriate parameters of control system and strategy could realize shift process control.

Simulation research on automatic transmission shift schedule is carried out based on virtual calibration technology. Firstly, a high-precision engine model, transmission model and physical models of the entire vehicle and its main components are established. The transmission control model is built using known TCU control strategies or directly connected to the TCU controller on the virtual simulation platform. The Hardware-in-the-Loop (HiL) simulation platform is used to conduct TCU calibration related working conditions simulation testing, and the simulation results are compared with experimental data. The research results indicate that this model-based virtual calibration technology can meet the accuracy requirements in the field of shift schedule calibration and can be used to guide vehicle shift schedule calibration, effectively shortening calibration time and improving calibration quality.

A three-dimensional simulation model of leaf spring with few piece variable cross-section with crack is established using SolidWorks and ANSYS. The influence laws of crack location, angle, and depth on the stiffness of few leaf spring are explored by analyzing stiffness characteristics of few leaf spring under different crack locations, angles and depths. The results show that the transverse crack has a significant influence on the stiffness of the leaf spring. The closer the crack location is to the 1/3 length of the straight section at the root of the leaf spring, the closer the crack angle is to 90° and the deeper the crack is, the greater the influence is and the smaller the stiffness is. The longitudinal crack has a slight influence on the stiffness of the leaf spring and the variation of the stiffness is small. The stiffness of the leaf spring with crack is slightly bigger than that of the leaf spring without crack in a certain depth range.

In order to discover the effects of automotive Continuous Damping Control (CDC) shock absorber solenoid valve on electromagnetic force, the two-dimensional simulation model of CDC shock absorber solenoid valve is established under ANSYS Maxwell environment, and working air gap, material properties, moving iron core radius and other parameters are simulated and analyzed to obtain the relation curve of electromagnetic force of CDC shock absorber solenoid valve with each parameter. The influence of different structural parameters on electromagnetic force of CDC shock absorber solenoid valve is analyzed. The results show that electromagnet properties and moving iron core radius have a great impact on solenoid force and displacement relation curve. The solenoid valve can be optimized by changing related parameters.

The phase angle lead characteristic and the amplitude attenuation characteristic of the lag network can be used to improve the performance of the lead and lag corrector system. Therefore, for the stability of Electric Power Steering (EPS) system, an optimization scheme based on lead and lag corrector is proposed. Firstly, the state space equation of EPS system is established based on the steering system dynamics theory and the system transfer function is obtained. Secondly, the open loop transfer function is derived based on the system transfer function, and the influence of the lead and lag corrector on the stability of EPS system is analyzed by simulation. Finally, forward development and design are deployed for lead and lag parameters development. The results show that the amplitude margin, phase Angle margin and cutoff frequency of the open loop transfer function after correction are obviously improved compared with that before correction, and the designed lead lag corrector can greatly improve the stability of EPS system.

In order to optimize the torque fluctuation of the cross-axis universal joint steering system of a certain vehicle model,By extracting the coordinates of key hard points of the steering system in the CATIA three-dimensional digital model of this vehicle model, a simplified simulation model of the steering system is established by using ADAMS/View software.Under the condition of not changing the installation hard points of the steering system, the phase angle of the transmission shaft that can minimize the torque fluctuation of the steering system is obtained through simulation.The results of subjective evaluation and real vehicle verification show that the optimization result of simulation data is consistent with the theoretical calculation result, ensuring the minimum torque fluctuation of the steering system.