Modelling And Dynamic Behavior Of A Vibratory Roller For Soil Compacting Based On Lumped-Parameter Method

With the heavy and rapid development of road transportation,the early damage to the road surface is becoming more and more serious.How to solve the problem from the root has become the focus of research.Soil compaction is one of the important links in the roadbed construction process,which directly affects the uniformity and stability of the road surface.Therefore,this article focuses on the vibratory roller system.This study takes the "vibratory roller-soil" system as the research object.Based on the lumped-parameter method,the dynamic models under different working conditions were established and the models were solved.The dynamic behavior of the system was simulated for certain operation conditions to reveal the dynamic characteristics of the system and clarify the interaction characteristics of the drum and the soil.The research enriches the theory of vibration compaction and provides a basis for the adjustment of roller parameters.Based on the analysis,some main conclusions can be drawn.(1)The two-degree-of-freedom roller-soil lumped-parameter model has two natural frequencies.With the continuous compaction of the soil,the natural frequencies of the system show an increasing trend.The vibration frequency of the roller should be slightly less than the second-order natural frequency of the system.As the stiffness of the soil increases and the damping decreases,the drum may jump or even double jump.At this time,the frequency of the exciting force should be appropriately increased or the amplitude should be reduced.Relatively speaking,the system is more sensitive to frequency.(2)Considering the surface irregularity of the soil,a 2D linear dynamic model of roller-soil system was established for the vibratory roller and well-compacted soil.Under certain conditions,the excitation of the soil surface could play a significant role for the system response,therefore the frequency of the surface excitation should be controlled within a reasonable range.For smooth operating conditions where the drum is in contact with the soil,the impact of the ground surface excitation on the system acceleration response is much smaller than the vibrating force of the drum,and its impact can be ignored when analyzing the dynamic behavior of the roller system.(3)Based on the feedback of the speed difference,a fractional PID control model of the roller and the soil was established.The first-order approximate solution of the system was obtained by the averaging method,and the calculation time was obviously shorter than that of the numerical method.The stability of the model was s verified by using the Lyapunov stability theorem.According to the control variable method,the influence of various parameters on the dynamic behavior of the system was studied,and it was proved that the control effect of the fractional-order PID control is better than that of the integer-order PID control.(4)The non-linear model is suitable for the early stage of compaction when the plastic deformation of the soil is large.Compared with the linear model,it was found that the output response of the system is no longer a sine wave.The vibration of the frame in the steady state of the nonlinear model is larger,but the vibration of the drum is smaller.The influence of the roller parameters on the dynamic behavior of the system is similar.