Study On Ride Comfort And Road Friendliness Of Semi-active Suspension Of Heavy-duty Combination Vehicles

In recent years, with the rapid development of Chinese highways and as a result of modern transport needs, highway freight traffic to further intensification and specialization, heavy vehicles, especially semi-trailer train have also been developed rapidly. As the working conditions of heavy vehicles are often quite poor , more curve, more than a pathway, turning radius smaller, and the vehicles steer and brake frequently during the running, and also work in full, vibration and under shock loads in long-term, so the road and Transport goods were severely damaged. Suspension is an important part of the combination vehicles. Whether the suspension quality is good, not only affect the combination vehicles ride comfort, but also affect the handling and stability, negotiation performance and so on. At present, air suspension applied on the heavy-duty truck abroad at the rate of 85%; about 80% of trailers using air suspension. However, there is still a long way to go for the air suspension domestic application.In order to improve the comfort of drivers and passengers and road-friendliness, based on the parameters of some semi-trailer train model, the dynamics model of semi-trailer train was built in this paper, and also the dynamic equations was translated to into state space equation, road - vehicle- people simulation system diagram was set up in Matlab / Simulink to carry on the dynamic system simulation. As the tractor suspension system,nonlinear strong, and fuzzy control system was suitable for nonlinear time-varying model, also with simple modeling and high control precision. For the characteristics of the tractor, multi-fuzzy controllers were designed. Using Simulink toolbox, the dynamic performance of the tractor with semi-active air suspension system,was carried out at the same speed, with different road A, B, C class road. The data was handled by joining Matlab and post-processing of ADAMS, with data analysis efficiency and precision improved. According to the simulation of experimental data, the simulation results, such as: tractor center of mass acceleration and displacement, cab and seat displacement parameters, affecting ride comfort and handling stability indicators, which were compared with the RMS in time domain and with the PSD in frequency domain. The three evaluating indicators, dynamic load factor, dynamic load stress factor and the 95 percentile comprehensive four times, were evaluated for the vehicle road-friendly on the B-class road. Simulation results showed that: after the fuzzy control of semi-active air suspension, center of mass acceleration improved up to more than 30% , the peak PSD frequency in domain were decreased, and in the end preferably the ride comfort were improved. The dynamic load factor of B-class roads after control, the tire load reduced the damaging effects of the road reduced, road-friendly improved. Also it was showed that the fuzzy controllers designed in this paper had some capacity to adapt.