The Dynamic Characteristics Of The Manned Maneuvering Motorcycle And Ride Comfort

With the improvement of living standard, more comfortable motorcycle is required. In this thesis, a new method to improve dynamic behaviours is put forward by studying the GS-125 motorcycle.A rigid rider-motorcycle dynamic model considering the position of rider is firstly-set up by means of the 3-D modeling and mechanical dynamic analysis technology. The flexible dynamic model is also established on the basis of FEM and mechanical dynamic analysis technology.Then, the rigid and the flexible model are verified by the experimental modal analysis. The dynamic characteristics of the rider-motorcycle system above are thoroughly analyzed.The results show that the frequency of mode shape of rider's vibration in vertical caused by the front and rear suspension is 4.49Hz, which is within the sensitive frequency range of the rider's chest and abdomen system. So, the structure of motorcycle must be improved. There are high frequencies in the flexible model that cannot be obtained from the rigid one, which contribute to the noise of motorcycle. The results also reveal that the flexible multibody system is more accurate than the rigid multibody system.The influences of the rider's mass, the parameters of the front and the rear suspension systems, and even rider position on the natural frequency of motorcycle system are also studied based on the two developed models above. The results show that most of the frequencies decrease with the driver's mass and a majority of frequencies of the main shapes increase with the stiffness of the suspension spring and rider position has a great influence on the frequencies.Finally, according to the response of the rider to the rider-motorcycle vibration system, the concept of ride comfort design of motorcycle is put forward. To improve ride comfort, the parameters of suspension systems, tire and rider position should be considered together.A new method for analyzing the dynamic behaviours of a complicated multibodysystem dynamics is provided and an applicable example is given.