| With the rapid growth of the national economy,road freight has become an important part of China's comprehensive transportation system,and the tractor semitrailer play an important role in the road freight industry due to its high transportation efficiency and good driving stability.However,due to the influence of road surface impact during long-term and long-distance driving,the tractor semi-trailer driver are likely to be fatigued,posing a potential threat to the driver's life and the safe driving of other road vehicles.Therefore,it is of great significance to study the semi-active suspension system that can improve both ride comfort and driving safety of tractor semi-trailer.In this paper,a six-axle tractor semi-trailer is taken as the research object.By introducing a variable damping magnetorheological damper,a semi-active suspension model with adjustable damping of tractor semi-trailer is established,and different control strategies are designed to analyze the influence of the semi-active suspension model with adjustable damp on the ride comfort and safety of tractor semi-trailer.The main work is as follows: 1)The composition and working mode of magnetorheological fluid were expounded,and analyzed the advantages and disadvantages of several common magnetorheological damper mechanical models.The simulation model of Bou-Wen modified model was built and discussed the relationship between the damping force and the excitation displacement and the change of the excitation speed under different voltage inputs.2)Using the filter white noise method,the random road surface excitation model was constructed.Based on the reasonable assumptions,the simplified vibration mechanics model of the tractor semi-trailer was established,and the vehicle vibration system simulation model was built by Simulink software.3)To explore its influence on ride comfort,simulation analysis for the vehicle model was conducted by changing the suspension structure parameters of the tractor and semitrailer.Based on this,the semi-active suspension vibration dynamics model with tractor as control object was established.4)Based on the semi-active suspension model with adjustable damping of tractor semi-trailer,three control strategies,such as skyhook control,sky-ground hook mixing control and fuzzy hybrid control,were used to design the corresponding controller,and its effectiveness was verified by simulation.The simulation results show that the three control strategies can improve the ride comfort of the tractor semi-trailer to a certain extent.5)In order to explore the influence of different control strategies on the ride comfort and driving safety of tractor semi-trailer,the control effects of each controller were analyzed from the two layers of time domain and frequency domain.The results show that the skyhook control strategy is superior to the sky-ground hook mixing and fuzzy hybrid control strategy in improving the ride comfort,but it is weaker than the latter two in reducing the dynamic displacement of the suspension and the relative dynamic load of the tire,and even has a deteriorating effect.Compared with the former two control strategies,the fuzzy hybrid control strategy not only attenuates the vibration acceleration of the main vibrating components well,but also reduces the suspension dynamic displacement and the relative dynamic load of the tire in a certain range,which gives a good balance between ride comfort and driving safety. |
PDF Full Text Request