3 research outputs found
Contribution to the research of oscillatory loads of sprung and unsprung masses in order to create conditions for laboratory tests of heavy motor vehicles
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
Modeling and simulation of hydraulic buffering valve for power-shift transmission
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
Mathematical modeling and simulation of a half-vehicle suspension system in the roll plane
Introduction/purpose: The study of vehicle suspension is a challenge for researchers in the field of vehicles regarding the impact of the suspension system on vehicle performances such as ride comfort, road holding, and working space. This paper presents the simulation of the Land Rover Defender 110 vehicle in the roll plane (half vehicle) in Simulink/MATLAB. The obtained results were compared with the results obtained in the ADAMS/CAR software package of the Land Rover Defender 110 simulation model previously experimentally validated. The Defender 110 vehicle has a dependent suspension system in both axles and a passive suspension type with four degrees of freedom (4 DOF). Methods: The equations of the system can be solved mathematically with a scheme in Simulink/MATLAB while half-vehicle modeling has been done in ADAMS/CAR. Results: The comparison of the vehicle characteristics obtained by the two simulation methods was done for three different scenarios, and it was noticed that there is a good correlation between them. Conclusion: It was concluded that the Defender 110 vehicle simulation model in Simulink/MATLAB is validated. The validated model can be used to perform suspension system optimization in future work