Dynamical Analysis Of Heavy-duty Truck Considering The Clearance Of Balanced Suspension

Aiming at the difficulties of building vehicle model,a discrete dynamical model of heavy-duty truck based on system constraint has been proposed,and dynamical analysis was made based on the model.The basic theory of the model is the Udwadia and Kalaba's multi-body dynamical system.Assumed that the body of the truck can be equivalented to 9 particles and the front shaft and the roar shaft can be equivalented to 3 particles respectively,then added the constrained system into particles system to form the completed dynamical system.The situation that four tires' loads generated by road are different during normal operation is within considered.We mainly researched the dynamical characteristics of z direction of each particle and the driver.Though simulation by Matlab,we got the graph of each particles under the condition of unload.Compared with the graph which is generated by Lagrange model,we proved the correctness of the dynamical model.Chose road that belongs to level D as the input condition,got the simulation graph dynamic characteristic of key particles and driver.Aiming at solving the problem that the existence of clearance in balanced shaft assembly during working.The assembly belongs to the balanced suspension of multishaft heavy-duty truck.Based on the operation principle of balanced shaft assembly in three-shaft truck and the theory of contact and friction,established a nonlinear kinematics model system in mathematics.Finally,the nonlinear model was added into the truck's dynamical function to form the nonlinear dynamical system of vehicle.The dynamical function was built baised on the half-vehicle model which is with 6 DOF.The situation that three tires' loads generated by road are different during normal operation is within considered.We mainly researched the dynamical characteristics of rotation and displacement on vertical direction of body and the driver's displacement on vertical direction.The corresponding simulation programs for the system were developed by MATLAB and got the dynamical characteristic curves.Then compared with the curve which was generated by the ideal model to show the influence of clearance,generated by balanced shaft assembly,in dynamical characteristic of heavy-duty truck system.Built the discrete dynamical model for three-shaft heavy-duty truck by the theory of Udwadia-Kalaba.Bracketed subsystems by the condition of movement form and modeled in group,which made the process organized.Added the nolinear kinematic model of balanced suspension system into the discrete model,so a nolinear vehicle dynamical system wich 20 DOF was formed.Solved and optimized the nolinear system and we can get the displacement and acceleration response signal of driver in z direction in time domain.Evaluated the system comprehensively by signal's PSD and RMS.