The vehicle steering system is one of the most important systems on the vehicle, both in terms of safety and performance. Based on the geometry of the steering trapezoid, the geometry of the suspension system, the alignment angles of the wheels, as well as the characteristics of the tires, a mathematical model for the design of the formula student vehicle "Road Arrow" steering system was developed. Based on the dynamic state of the vehicle, the mathematical model provides information on the stress of the steering system, the torque on the steering wheel and the slip angles of the steered wheels. The mathematical model was developed using the MATLAB software, and validation of the results was performed by comparing the results with the ones obtained by simulations in MSC ADAMS. Analysing the obtained results, it is possible to conclude that the average value of relative error of the stress is approximately 15%, for slip angles of the steered wheels is approximately 7%, and the error for torque on the steering wheel is approximately 6%.

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Introduction/purpose: Motor vehicles are complex dynamic systems due to spatial displacements, changes in the characteristics of components during their lifetime, a large number of influences and disturbances, the appearance of backlash, friction, hysteresis, etc. The aforementioned dynamic phenomena, especially vibrations, cause driver and passenger fatigue, reduce the lifetime of the vehicle and its systems, etc. Methods: In general, the movement of vehicles is carried out on uneven roads and curvilinear paths in the road. Not only do oscillatory movements cause material fatigue of vehicle parts, but they also have a negative effect on people's health. That is why special attention must be paid to the coordination of the mutual movement of the subsystems, and in particular, the vehicle suspension system, even at the stage of the motor vehicle design. For these purposes, theoretical, experimental or combined methods can be used. Therefore, it is very useful to have the experimental results of the oscillations of the vehicle subsystem in operating conditions, so the aim of this work was to use the movement of the 4x4 drive FAP 1118 vehicle in operating conditions (due to higher speeds - in road conditions) to define the conditions for testing oscillatory loads in laboratory conditions. Results: This is made possible by registering and identifying statistical parameters of registered quantities. Conclusion: Based on the measured data, the research can be programmed on shakers in laboratory conditions, and, at the same time, the size to be reproduced can be chosen as well.

Motor vehicles are complex dynamic systems due to spatial vibratory displacements during movement, changes in the characteristics of components during life cycle, a large number of influences and disturbances, the occurrence of clearance, friction, hysteresis, etc. The mentioned dynamic phenomena, especially vibrations, cause fatigue of the driver and passengers, reduce the life cycle of the vehicle and its systems, etc. In the general case, the movement of motor vehicles is done on uneven roads (terrain) and curvilinear paths in flat roads (terrains). Oscillatory movements cause loading of vehicle parts, but they also negatively affect human health. Therefore, even in the design phase of the vehicle, special attention must be paid to the harmonization of the mutual movement of the vehicle subsystem, and in particular, the suspension system. Theoretical, experimental or combined methods can be used for this purpose, and it is very useful to have experimental results of vibration of the vehicle subsystems in real operational conditions. Therefore, it is very useful to have experimental results of vibration of vehicle subsystems in operational conditions. Bearing that in mind, the aim of this wpaper was to use the movement of FAP 1118, 4x4 wheel formula, in operational conditions (due to higher speeds - in road conditions) to define laboratory conditions for testing. This is made possible by registering and identifying statistical parameters of registered quantities.

Introduction/purpose: The hydraulic buffering valve has the greatest influence on the dynamic characteristics of power-shift transmission. The hydraulic buffering valve is a transmission element that controls increase in pressure in friction assemblies during the gear shifting process. By choosing the optimal control of pressure increase during shifting, reduction of dynamic loads in gear transmissions and thermal loads in friction assemblies is achieved. Methods: The paper analyzes the principle of one of hydraulic buffering valve solutions as well as the influence of certain parameters on the control of pressure increase. After the analysis of the working principle of the hydraulic buffering valve, a simulation model was developed in the MATLAB/Simulink software package. Results: The results obtained using the simulation model were compared with the experimental results of the selected pressure modulator solution. The selected hydraulic buffering valve was developed as part of the development of a device for power-shift transmission. The simulation results showed a satisfactory match with the experimental results. Conclusion: The developed simulation model enables a relatively easy and quick change of the parameters of the hydraulic buffering valve as well as a possibility of a faster and better understanding of the influence of individual parameters on pressure increase during the gear shifting process.