No abstract

The vehicle planar single track dynamic model with two input steering angle parameters is derived by using Lagrange's method with the basis of equations for calculating the tire's force components. Dynamic analysis of a heavy articulated vehicle in case of turing is carried out by the vehicle planar dynamic model, in which two input steering angles are taken into account. Simulation with the selected velocity value to make sure that the stability according to the friction conditions at all axles of the vehicle is satisfied. Turning spacing, lateral forces at each axle of the vehicle are determined and analyzed for all three different cases of steering angles, respectively with steering angle of the semi-trailer is in the same direction, in the opposite direction and is locked or not steered in comparision with the steering angle of the tractor. The obtained results show that the derived model could employ to determine the planar kinematic and dynamic parameters, and analyze the dynamic safety features of an articulated vehicle, too. In addition, the derived mathematical model could also employ to develop a computational model that controls the planar articulated vehicle dynamics.

The powertrain model of a vehicle using a small gasoline engine is designed based on the analysis results of the Matlab/Simdriveline simulation model. In which, the vehicle's powertrain model parts include: engine, clutch, gearbox, differential and wheels, and overall vehicle modeled by Matlab/ Simdriveline. Mathematical basis of the corresponding models for systems or components are used to build simulated models for the entire vehicle's powertrain system. The input parameters for the simulation problem include parameters of the size, mass, structural and technical parameters of each system such as transmission ratio, power, velocity, efficiency, determined based on actual vehicle model and empirical calculations. The simulation calculation process is done on the basis of the variation of the engine power, from which, the corresponding input and output kinetic and dynamic parameters of each system in the powertrain system consists of clutch, gearbox, differential, are obtained in the time domain. The results of simulation calculation of the kinematics and dynamics of each system in the vehicle's powertrain are analyzed as a basis for design improvement to improve the dynamic performance of the vehicle model.

Vehicle dynamics model in type of 1/4 is used for vibration analysis under the effect of random road profile with different grades. The mathematical model to describe the used random road profile is able to change the type of investigated road grades by selecting the corresponding power spectral density parameter of the road grade according to the ISO 8608 standard. Random road profile is ivestigated in the range of frequency domain from 0 to 50 (Hz). The air spring stiffness and the damping coefficience are determined on the basis of reference to the practical vehicle. The variation of relative displacement amplitude of the suspension in the range of investigation domain is small, the air spring stiffness used in the calculation is constant. The obtained results corresponding to different grades of road surface roughness including displacement and acceleration parameters. Relative displacement is a parameter that aims to verify the ability to ensure safe working of the suspension, namely rattle spacing. Acceleration is used to evaluate the vehicle's comfort. Calculation results are analyzed as the basis for evaluating the influence of the air spring stiffness and road surface conditions on the comfort of the vehicle, as the basis for changing the air spring stiffness in accordance with adjusting the pressure of it according to the type of road profile quality.